Commit 66bb6a58 authored by Spark's avatar Spark Committed by KangMin An
Browse files

typescript client

parent 0d025f8d
const conversions = require('./conversions');
/*
This function routes a model to all other models.
all functions that are routed have a property `.conversion` attached
to the returned synthetic function. This property is an array
of strings, each with the steps in between the 'from' and 'to'
color models (inclusive).
conversions that are not possible simply are not included.
*/
function buildGraph() {
const graph = {};
// https://jsperf.com/object-keys-vs-for-in-with-closure/3
const models = Object.keys(conversions);
for (let len = models.length, i = 0; i < len; i++) {
graph[models[i]] = {
// http://jsperf.com/1-vs-infinity
// micro-opt, but this is simple.
distance: -1,
parent: null
};
}
return graph;
}
// https://en.wikipedia.org/wiki/Breadth-first_search
function deriveBFS(fromModel) {
const graph = buildGraph();
const queue = [fromModel]; // Unshift -> queue -> pop
graph[fromModel].distance = 0;
while (queue.length) {
const current = queue.pop();
const adjacents = Object.keys(conversions[current]);
for (let len = adjacents.length, i = 0; i < len; i++) {
const adjacent = adjacents[i];
const node = graph[adjacent];
if (node.distance === -1) {
node.distance = graph[current].distance + 1;
node.parent = current;
queue.unshift(adjacent);
}
}
}
return graph;
}
function link(from, to) {
return function (args) {
return to(from(args));
};
}
function wrapConversion(toModel, graph) {
const path = [graph[toModel].parent, toModel];
let fn = conversions[graph[toModel].parent][toModel];
let cur = graph[toModel].parent;
while (graph[cur].parent) {
path.unshift(graph[cur].parent);
fn = link(conversions[graph[cur].parent][cur], fn);
cur = graph[cur].parent;
}
fn.conversion = path;
return fn;
}
module.exports = function (fromModel) {
const graph = deriveBFS(fromModel);
const conversion = {};
const models = Object.keys(graph);
for (let len = models.length, i = 0; i < len; i++) {
const toModel = models[i];
const node = graph[toModel];
if (node.parent === null) {
// No possible conversion, or this node is the source model.
continue;
}
conversion[toModel] = wrapConversion(toModel, graph);
}
return conversion;
};
The MIT License (MIT)
Copyright (c) 2015 Dmitry Ivanov
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
\ No newline at end of file
A JSON with color names and its values. Based on http://dev.w3.org/csswg/css-color/#named-colors.
[![NPM](https://nodei.co/npm/color-name.png?mini=true)](https://nodei.co/npm/color-name/)
```js
var colors = require('color-name');
colors.red //[255,0,0]
```
<a href="LICENSE"><img src="https://upload.wikimedia.org/wikipedia/commons/0/0c/MIT_logo.svg" width="120"/></a>
'use strict'
module.exports = {
"aliceblue": [240, 248, 255],
"antiquewhite": [250, 235, 215],
"aqua": [0, 255, 255],
"aquamarine": [127, 255, 212],
"azure": [240, 255, 255],
"beige": [245, 245, 220],
"bisque": [255, 228, 196],
"black": [0, 0, 0],
"blanchedalmond": [255, 235, 205],
"blue": [0, 0, 255],
"blueviolet": [138, 43, 226],
"brown": [165, 42, 42],
"burlywood": [222, 184, 135],
"cadetblue": [95, 158, 160],
"chartreuse": [127, 255, 0],
"chocolate": [210, 105, 30],
"coral": [255, 127, 80],
"cornflowerblue": [100, 149, 237],
"cornsilk": [255, 248, 220],
"crimson": [220, 20, 60],
"cyan": [0, 255, 255],
"darkblue": [0, 0, 139],
"darkcyan": [0, 139, 139],
"darkgoldenrod": [184, 134, 11],
"darkgray": [169, 169, 169],
"darkgreen": [0, 100, 0],
"darkgrey": [169, 169, 169],
"darkkhaki": [189, 183, 107],
"darkmagenta": [139, 0, 139],
"darkolivegreen": [85, 107, 47],
"darkorange": [255, 140, 0],
"darkorchid": [153, 50, 204],
"darkred": [139, 0, 0],
"darksalmon": [233, 150, 122],
"darkseagreen": [143, 188, 143],
"darkslateblue": [72, 61, 139],
"darkslategray": [47, 79, 79],
"darkslategrey": [47, 79, 79],
"darkturquoise": [0, 206, 209],
"darkviolet": [148, 0, 211],
"deeppink": [255, 20, 147],
"deepskyblue": [0, 191, 255],
"dimgray": [105, 105, 105],
"dimgrey": [105, 105, 105],
"dodgerblue": [30, 144, 255],
"firebrick": [178, 34, 34],
"floralwhite": [255, 250, 240],
"forestgreen": [34, 139, 34],
"fuchsia": [255, 0, 255],
"gainsboro": [220, 220, 220],
"ghostwhite": [248, 248, 255],
"gold": [255, 215, 0],
"goldenrod": [218, 165, 32],
"gray": [128, 128, 128],
"green": [0, 128, 0],
"greenyellow": [173, 255, 47],
"grey": [128, 128, 128],
"honeydew": [240, 255, 240],
"hotpink": [255, 105, 180],
"indianred": [205, 92, 92],
"indigo": [75, 0, 130],
"ivory": [255, 255, 240],
"khaki": [240, 230, 140],
"lavender": [230, 230, 250],
"lavenderblush": [255, 240, 245],
"lawngreen": [124, 252, 0],
"lemonchiffon": [255, 250, 205],
"lightblue": [173, 216, 230],
"lightcoral": [240, 128, 128],
"lightcyan": [224, 255, 255],
"lightgoldenrodyellow": [250, 250, 210],
"lightgray": [211, 211, 211],
"lightgreen": [144, 238, 144],
"lightgrey": [211, 211, 211],
"lightpink": [255, 182, 193],
"lightsalmon": [255, 160, 122],
"lightseagreen": [32, 178, 170],
"lightskyblue": [135, 206, 250],
"lightslategray": [119, 136, 153],
"lightslategrey": [119, 136, 153],
"lightsteelblue": [176, 196, 222],
"lightyellow": [255, 255, 224],
"lime": [0, 255, 0],
"limegreen": [50, 205, 50],
"linen": [250, 240, 230],
"magenta": [255, 0, 255],
"maroon": [128, 0, 0],
"mediumaquamarine": [102, 205, 170],
"mediumblue": [0, 0, 205],
"mediumorchid": [186, 85, 211],
"mediumpurple": [147, 112, 219],
"mediumseagreen": [60, 179, 113],
"mediumslateblue": [123, 104, 238],
"mediumspringgreen": [0, 250, 154],
"mediumturquoise": [72, 209, 204],
"mediumvioletred": [199, 21, 133],
"midnightblue": [25, 25, 112],
"mintcream": [245, 255, 250],
"mistyrose": [255, 228, 225],
"moccasin": [255, 228, 181],
"navajowhite": [255, 222, 173],
"navy": [0, 0, 128],
"oldlace": [253, 245, 230],
"olive": [128, 128, 0],
"olivedrab": [107, 142, 35],
"orange": [255, 165, 0],
"orangered": [255, 69, 0],
"orchid": [218, 112, 214],
"palegoldenrod": [238, 232, 170],
"palegreen": [152, 251, 152],
"paleturquoise": [175, 238, 238],
"palevioletred": [219, 112, 147],
"papayawhip": [255, 239, 213],
"peachpuff": [255, 218, 185],
"peru": [205, 133, 63],
"pink": [255, 192, 203],
"plum": [221, 160, 221],
"powderblue": [176, 224, 230],
"purple": [128, 0, 128],
"rebeccapurple": [102, 51, 153],
"red": [255, 0, 0],
"rosybrown": [188, 143, 143],
"royalblue": [65, 105, 225],
"saddlebrown": [139, 69, 19],
"salmon": [250, 128, 114],
"sandybrown": [244, 164, 96],
"seagreen": [46, 139, 87],
"seashell": [255, 245, 238],
"sienna": [160, 82, 45],
"silver": [192, 192, 192],
"skyblue": [135, 206, 235],
"slateblue": [106, 90, 205],
"slategray": [112, 128, 144],
"slategrey": [112, 128, 144],
"snow": [255, 250, 250],
"springgreen": [0, 255, 127],
"steelblue": [70, 130, 180],
"tan": [210, 180, 140],
"teal": [0, 128, 128],
"thistle": [216, 191, 216],
"tomato": [255, 99, 71],
"turquoise": [64, 224, 208],
"violet": [238, 130, 238],
"wheat": [245, 222, 179],
"white": [255, 255, 255],
"whitesmoke": [245, 245, 245],
"yellow": [255, 255, 0],
"yellowgreen": [154, 205, 50]
};
{
"name": "color-name",
"version": "1.1.4",
"description": "A list of color names and its values",
"main": "index.js",
"files": [
"index.js"
],
"scripts": {
"test": "node test.js"
},
"repository": {
"type": "git",
"url": "git@github.com:colorjs/color-name.git"
},
"keywords": [
"color-name",
"color",
"color-keyword",
"keyword"
],
"author": "DY <dfcreative@gmail.com>",
"license": "MIT",
"bugs": {
"url": "https://github.com/colorjs/color-name/issues"
},
"homepage": "https://github.com/colorjs/color-name"
}
Copyright (c) 2017-2018 Fredrik Nicol
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
# CSSType
[![npm](https://img.shields.io/npm/v/csstype.svg)](https://www.npmjs.com/package/csstype)
TypeScript and Flow definitions for CSS, generated by [data from MDN](https://github.com/mdn/data). It provides autocompletion and type checking for CSS properties and values.
**TypeScript**
```ts
import * as CSS from 'csstype';
const style: CSS.Properties = {
colour: 'white', // Type error on property
textAlign: 'middle', // Type error on value
};
```
**Flow**
```js
// @flow strict
import * as CSS from 'csstype';
const style: CSS.Properties<> = {
colour: 'white', // Type error on property
textAlign: 'middle', // Type error on value
};
```
_Further examples below will be in TypeScript!_
## Getting started
```sh
$ npm install csstype
$ # or
$ yarn add csstype
```
## Table of content
- [Style types](#style-types)
- [At-rule types](#at-rule-types)
- [Pseudo types](#pseudo-types)
- [Generics](#generics)
- [Usage](#usage)
- [What should I do when I get type errors?](#what-should-i-do-when-i-get-type-errors)
- [Version 3.0](#version-30)
- [Contributing](#contributing)
## Style types
Properties are categorized in different uses and in several technical variations to provide typings that suits as many as possible.
| | Default | `Hyphen` | `Fallback` | `HyphenFallback` |
| -------------- | -------------------- | -------------------------- | ---------------------------- | ---------------------------------- |
| **All** | `Properties` | `PropertiesHyphen` | `PropertiesFallback` | `PropertiesHyphenFallback` |
| **`Standard`** | `StandardProperties` | `StandardPropertiesHyphen` | `StandardPropertiesFallback` | `StandardPropertiesHyphenFallback` |
| **`Vendor`** | `VendorProperties` | `VendorPropertiesHyphen` | `VendorPropertiesFallback` | `VendorPropertiesHyphenFallback` |
| **`Obsolete`** | `ObsoleteProperties` | `ObsoletePropertiesHyphen` | `ObsoletePropertiesFallback` | `ObsoletePropertiesHyphenFallback` |
| **`Svg`** | `SvgProperties` | `SvgPropertiesHyphen` | `SvgPropertiesFallback` | `SvgPropertiesHyphenFallback` |
Categories:
- **All** - Includes `Standard`, `Vendor`, `Obsolete` and `Svg`
- **`Standard`** - Current properties and extends subcategories `StandardLonghand` and `StandardShorthand` _(e.g. `StandardShorthandProperties`)_
- **`Vendor`** - Vendor prefixed properties and extends subcategories `VendorLonghand` and `VendorShorthand` _(e.g. `VendorShorthandProperties`)_
- **`Obsolete`** - Removed or deprecated properties
- **`Svg`** - SVG-specific properties
Variations:
- **Default** - JavaScript (camel) cased property names
- **`Hyphen`** - CSS (kebab) cased property names
- **`Fallback`** - Also accepts array of values e.g. `string | string[]`
## At-rule types
At-rule interfaces with descriptors.
**TypeScript**: These will be found in the `AtRule` namespace, e.g. `AtRule.Viewport`.
**Flow**: These will be prefixed with `AtRule$`, e.g. `AtRule$Viewport`.
| | Default | `Hyphen` | `Fallback` | `HyphenFallback` |
| -------------------- | -------------- | -------------------- | ---------------------- | ---------------------------- |
| **`@counter-style`** | `CounterStyle` | `CounterStyleHyphen` | `CounterStyleFallback` | `CounterStyleHyphenFallback` |
| **`@font-face`** | `FontFace` | `FontFaceHyphen` | `FontFaceFallback` | `FontFaceHyphenFallback` |
| **`@viewport`** | `Viewport` | `ViewportHyphen` | `ViewportFallback` | `ViewportHyphenFallback` |
## Pseudo types
String literals of pseudo classes and pseudo elements
- `Pseudos`
Extends:
- `AdvancedPseudos`
Function-like pseudos e.g. `:not(:first-child)`. The string literal contains the value excluding the parenthesis: `:not`. These are separated because they require an argument that results in infinite number of variations.
- `SimplePseudos`
Plain pseudos e.g. `:hover` that can only be **one** variation.
## Generics
All interfaces has two optional generic argument to define length and time: `CSS.Properties<TLength = string | 0, TTime = string>`
- **Length** is the first generic parameter and defaults to `string | 0` because `0` is the only [length where the unit identifier is optional](https://drafts.csswg.org/css-values-3/#lengths). You can specify this, e.g. `string | number`, for platforms and libraries that accepts any numeric value as length with a specific unit.
```tsx
const style: CSS.Properties<string | number> = {
width: 100,
};
```
- **Time** is the second generic argument and defaults to `string`. You can specify this, e.g. `string | number`, for platforms and libraries that accepts any numeric value as length with a specific unit.
```tsx
const style: CSS.Properties<string | number, number> = {
transitionDuration: 1000,
};
```
## Usage
```ts
import * as CSS from 'csstype';
const style: CSS.Properties = {
width: '10px',
margin: '1em',
};
```
In some cases, like for CSS-in-JS libraries, an array of values is a way to provide fallback values in CSS. Using `CSS.PropertiesFallback` instead of `CSS.Properties` will add the possibility to use any property value as an array of values.
```ts
import * as CSS from 'csstype';
const style: CSS.PropertiesFallback = {
display: ['-webkit-flex', 'flex'],
color: 'white',
};
```
There's even string literals for pseudo selectors and elements.
```ts
import * as CSS from 'csstype';
const pseudos: { [P in CSS.SimplePseudos]?: CSS.Properties } = {
':hover': {
display: 'flex',
},
};
```
Hyphen cased (kebab cased) properties are provided in `CSS.PropertiesHyphen` and `CSS.PropertiesHyphenFallback`. It's not **not** added by default in `CSS.Properties`. To allow both of them, you can simply extend with `CSS.PropertiesHyphen` or/and `CSS.PropertiesHyphenFallback`.
```ts
import * as CSS from 'csstype';
interface Style extends CSS.Properties, CSS.PropertiesHyphen {}
const style: Style = {
'flex-grow': 1,
'flex-shrink': 0,
'font-weight': 'normal',
backgroundColor: 'white',
};
```
Adding type checked CSS properties to a `HTMLElement`.
```ts
import * as CSS from 'csstype';
const style: CSS.Properties = {
color: 'red',
margin: '1em',
};
let button = document.createElement('button');
Object.assign(button.style, style);
```
## What should I do when I get type errors?
The goal is to have as perfect types as possible and we're trying to do our best. But with CSS Custom Properties, the CSS specification changing frequently and vendors implementing their own specifications with new releases sometimes causes type errors even if it should work. Here's some steps you could take to get it fixed:
_If you're using CSS Custom Properties you can step directly to step 3._
1. **First of all, make sure you're doing it right.** A type error could also indicate that you're not :wink:
- Some CSS specs that some vendors has implemented could have been officially rejected or haven't yet received any official acceptance and are therefor not included
- If you're using TypeScript, [type widening](https://blog.mariusschulz.com/2017/02/04/TypeScript-2-1-literal-type-widening) could be the reason you get `Type 'string' is not assignable to...` errors
2. **Have a look in [issues](https://github.com/frenic/csstype/issues) to see if an issue already has been filed. If not, create a new one.** To help us out, please refer to any information you have found.
3. Fix the issue locally with **TypeScript** (Flow further down):
- The recommended way is to use **module augmentation**. Here's a few examples:
```ts
// My css.d.ts file
import * as CSS from 'csstype';
declare module 'csstype' {
interface Properties {
// Add a missing property
WebkitRocketLauncher?: string;
// Add a CSS Custom Property
'--theme-color'?: 'black' | 'white';
// ...or allow any other property
[index: string]: any;
}
}
```
- The alternative way is to use **type assertion**. Here's a few examples:
```ts
const style: CSS.Properties = {
// Add a missing property
['WebkitRocketLauncher' as any]: 'launching',
// Add a CSS Custom Property
['--theme-color' as any]: 'black',
};
```
Fix the issue locally with **Flow**:
- Use **type assertion**. Here's a few examples:
```js
const style: $Exact<CSS.Properties<*>> = {
// Add a missing property
[('WebkitRocketLauncher': any)]: 'launching',
// Add a CSS Custom Property
[('--theme-color': any)]: 'black',
};
```
## Version 3.0
- **All property types are exposed with namespace**
TypeScript: `Property.AlignContent` (was `AlignContentProperty` before)
Flow: `Property$AlignContent`
- **All at-rules are exposed with namespace**
TypeScript: `AtRule.FontFace` (was `FontFace` before)
Flow: `AtRule$FontFace`
- **Data types are NOT exposed**
E.g. `Color` and `Box`. Because the generation of data types may suddenly be removed or renamed.
- **TypeScript hack for autocompletion**
Uses `(string & {})` for literal string unions and `(number & {})` for literal number unions ([related issue](https://github.com/microsoft/TypeScript/issues/29729)). Utilize `PropertyValue<T>` to unpack types from e.g. `(string & {})` to `string`.
- **New generic for time**
Read more on the ["Generics"](#generics) section.
- **Flow types improvements**
Flow Strict enabled and exact types are used.
## Contributing
**Never modify `index.d.ts` and `index.js.flow` directly. They are generated automatically and committed so that we can easily follow any change it results in.** Therefor it's important that you run `$ git config merge.ours.driver true` after you've forked and cloned. That setting prevents merge conflicts when doing rebase.
### Commands
- `yarn build` Generates typings and type checks them
- `yarn watch` Runs build on each save
- `yarn test` Runs the tests
- `yarn lazy` Type checks, lints and formats everything
This source diff could not be displayed because it is too large. You can view the blob instead.
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{
"name": "csstype",
"version": "3.0.8",
"main": "",
"types": "index.d.ts",
"description": "Strict TypeScript and Flow types for style based on MDN data",
"repository": "https://github.com/frenic/csstype",
"author": "Fredrik Nicol <fredrik.nicol@gmail.com>",
"license": "MIT",
"devDependencies": {
"@types/chokidar": "^2.1.3",
"@types/jest": "^26.0.20",
"@types/jsdom": "^16.2.6",
"@types/node": "^14.14.31",
"@types/prettier": "^2.2.1",
"@types/request": "^2.48.5",
"@types/turndown": "^5.0.0",
"chalk": "^4.1.0",
"chokidar": "^3.5.1",
"fast-glob": "^3.2.5",
"flow-bin": "^0.145.0",
"jest": "^26.6.3",
"jsdom": "^16.4.0",
"mdn-browser-compat-data": "git+https://github.com/mdn/browser-compat-data.git#60214baa97657c798dd7eac44b7bc73af4968033",
"mdn-data": "git+https://github.com/mdn/data.git#7f622300bb7e285a2cbce7db6f8ecd8f964a18eb",
"prettier": "^2.2.1",
"request": "^2.88.2",
"ts-jest": "^26.5.2",
"ts-node": "^9.1.1",
"tslint": "^6.1.3",
"tslint-config-prettier": "^1.18.0",
"turndown": "^7.0.0",
"typescript": "~4.2.2",
"yarn": "^1.22.10"
},
"scripts": {
"prepublish": "yarn install --cwd __tests__ && yarn install --cwd __tests__/__fixtures__",
"prepublishOnly": "tsc && npm run test:src && npm run build && ts-node --files prepublish.ts",
"update": "ts-node --files update.ts",
"build": "ts-node --files build.ts --start",
"watch": "ts-node --files build.ts --watch",
"lint": "tslint --exclude node_modules/**/* --exclude **/*.d.ts --fix **/*.ts",
"pretty": "prettier --write build.ts **/*.{ts,js,json,md}",
"lazy": "tsc && npm run lint && npm run pretty",
"test": "jest",
"test:src": "jest src.*.ts",
"test:dist": "jest dist.*.ts"
},
"files": [
"index.d.ts",
"index.js.flow"
],
"keywords": [
"css",
"style",
"typescript",
"flow",
"typings",
"types",
"definitions"
]
}
MIT License
Copyright (c) Facebook, Inc. and its affiliates.
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
# diff-sequences
Compare items in two sequences to find a **longest common subsequence**.
The items not in common are the items to delete or insert in a **shortest edit script**.
To maximize flexibility and minimize memory, you write **callback** functions as configuration:
**Input** function `isCommon(aIndex, bIndex)` compares items at indexes in the sequences and returns a truthy/falsey value. This package might call your function more than once for some pairs of indexes.
- Because your function encapsulates **comparison**, this package can compare items according to `===` operator, `Object.is` method, or other criterion.
- Because your function encapsulates **sequences**, this package can find differences in arrays, strings, or other data.
**Output** function `foundSubsequence(nCommon, aCommon, bCommon)` receives the number of adjacent items and starting indexes of each common subsequence. If sequences do not have common items, then this package does not call your function.
If N is the sum of lengths of sequences and L is length of a longest common subsequence, then D = N – 2L is the number of **differences** in the corresponding shortest edit script.
[_An O(ND) Difference Algorithm and Its Variations_](http://xmailserver.org/diff2.pdf) by Eugene W. Myers is fast when sequences have **few** differences.
This package implements the **linear space** variation with optimizations so it is fast even when sequences have **many** differences.
## Usage
To add this package as a dependency of a project, do either of the following:
- `npm install diff-sequences`
- `yarn add diff-sequences`
To use `diff` as the name of the default export from this package, do either of the following:
- `var diff = require('diff-sequences').default; // CommonJS modules`
- `import diff from 'diff-sequences'; // ECMAScript modules`
Call `diff` with the **lengths** of sequences and your **callback** functions:
```js
const a = ['a', 'b', 'c', 'a', 'b', 'b', 'a'];
const b = ['c', 'b', 'a', 'b', 'a', 'c'];
function isCommon(aIndex, bIndex) {
return a[aIndex] === b[bIndex];
}
function foundSubsequence(nCommon, aCommon, bCommon) {
// see examples
}
diff(a.length, b.length, isCommon, foundSubsequence);
```
## Example of longest common subsequence
Some sequences (for example, `a` and `b` in the example of usage) have more than one longest common subsequence.
This package finds the following common items:
| comparisons of common items | values | output arguments |
| :------------------------------- | :--------- | --------------------------: |
| `a[2] === b[0]` | `'c'` | `foundSubsequence(1, 2, 0)` |
| `a[4] === b[1]` | `'b'` | `foundSubsequence(1, 4, 1)` |
| `a[5] === b[3] && a[6] === b[4]` | `'b', 'a'` | `foundSubsequence(2, 5, 3)` |
The “edit graph” analogy in the Myers paper shows the following common items:
| comparisons of common items | values |
| :------------------------------- | :--------- |
| `a[2] === b[0]` | `'c'` |
| `a[3] === b[2] && a[4] === b[3]` | `'a', 'b'` |
| `a[6] === b[4]` | `'a'` |
Various packages which implement the Myers algorithm will **always agree** on the **length** of a longest common subsequence, but might **sometimes disagree** on which **items** are in it.
## Example of callback functions to count common items
```js
// Return length of longest common subsequence according to === operator.
function countCommonItems(a, b) {
let n = 0;
function isCommon(aIndex, bIndex) {
return a[aIndex] === b[bIndex];
}
function foundSubsequence(nCommon) {
n += nCommon;
}
diff(a.length, b.length, isCommon, foundSubsequence);
return n;
}
const commonLength = countCommonItems(
['a', 'b', 'c', 'a', 'b', 'b', 'a'],
['c', 'b', 'a', 'b', 'a', 'c'],
);
```
| category of items | expression | value |
| :----------------- | ------------------------: | ----: |
| in common | `commonLength` | `4` |
| to delete from `a` | `a.length - commonLength` | `3` |
| to insert from `b` | `b.length - commonLength` | `2` |
If the length difference `b.length - a.length` is:
- negative: its absolute value is the minimum number of items to **delete** from `a`
- positive: it is the minimum number of items to **insert** from `b`
- zero: there is an **equal** number of items to delete from `a` and insert from `b`
- non-zero: there is an equal number of **additional** items to delete from `a` and insert from `b`
In this example, `6 - 7` is:
- negative: `1` is the minimum number of items to **delete** from `a`
- non-zero: `2` is the number of **additional** items to delete from `a` and insert from `b`
## Example of callback functions to find common items
```js
// Return array of items in longest common subsequence according to Object.is method.
const findCommonItems = (a, b) => {
const array = [];
diff(
a.length,
b.length,
(aIndex, bIndex) => Object.is(a[aIndex], b[bIndex]),
(nCommon, aCommon) => {
for (; nCommon !== 0; nCommon -= 1, aCommon += 1) {
array.push(a[aCommon]);
}
},
);
return array;
};
const commonItems = findCommonItems(
['a', 'b', 'c', 'a', 'b', 'b', 'a'],
['c', 'b', 'a', 'b', 'a', 'c'],
);
```
| `i` | `commonItems[i]` | `aIndex` |
| --: | :--------------- | -------: |
| `0` | `'c'` | `2` |
| `1` | `'b'` | `4` |
| `2` | `'b'` | `5` |
| `3` | `'a'` | `6` |
## Example of callback functions to diff index intervals
Instead of slicing array-like objects, you can adjust indexes in your callback functions.
```js
// Diff index intervals that are half open [start, end) like array slice method.
const diffIndexIntervals = (a, aStart, aEnd, b, bStart, bEnd) => {
// Validate: 0 <= aStart and aStart <= aEnd and aEnd <= a.length
// Validate: 0 <= bStart and bStart <= bEnd and bEnd <= b.length
diff(
aEnd - aStart,
bEnd - bStart,
(aIndex, bIndex) => Object.is(a[aStart + aIndex], b[bStart + bIndex]),
(nCommon, aCommon, bCommon) => {
// aStart + aCommon, bStart + bCommon
},
);
// After the last common subsequence, do any remaining work.
};
```
## Example of callback functions to emulate diff command
Linux or Unix has a `diff` command to compare files line by line. Its output is a **shortest edit script**:
- **c**hange adjacent lines from the first file to lines from the second file
- **d**elete lines from the first file
- **a**ppend or insert lines from the second file
```js
// Given zero-based half-open range [start, end) of array indexes,
// return one-based closed range [start + 1, end] as string.
const getRange = (start, end) =>
start + 1 === end ? `${start + 1}` : `${start + 1},${end}`;
// Given index intervals of lines to delete or insert, or both, or neither,
// push formatted diff lines onto array.
const pushDelIns = (aLines, aIndex, aEnd, bLines, bIndex, bEnd, array) => {
const deleteLines = aIndex !== aEnd;
const insertLines = bIndex !== bEnd;
const changeLines = deleteLines && insertLines;
if (changeLines) {
array.push(getRange(aIndex, aEnd) + 'c' + getRange(bIndex, bEnd));
} else if (deleteLines) {
array.push(getRange(aIndex, aEnd) + 'd' + String(bIndex));
} else if (insertLines) {
array.push(String(aIndex) + 'a' + getRange(bIndex, bEnd));
} else {
return;
}
for (; aIndex !== aEnd; aIndex += 1) {
array.push('< ' + aLines[aIndex]); // delete is less than
}
if (changeLines) {
array.push('---');
}
for (; bIndex !== bEnd; bIndex += 1) {
array.push('> ' + bLines[bIndex]); // insert is greater than
}
};
// Given content of two files, return emulated output of diff utility.
const findShortestEditScript = (a, b) => {
const aLines = a.split('\n');
const bLines = b.split('\n');
const aLength = aLines.length;
const bLength = bLines.length;
const isCommon = (aIndex, bIndex) => aLines[aIndex] === bLines[bIndex];
let aIndex = 0;
let bIndex = 0;
const array = [];
const foundSubsequence = (nCommon, aCommon, bCommon) => {
pushDelIns(aLines, aIndex, aCommon, bLines, bIndex, bCommon, array);
aIndex = aCommon + nCommon; // number of lines compared in a
bIndex = bCommon + nCommon; // number of lines compared in b
};
diff(aLength, bLength, isCommon, foundSubsequence);
// After the last common subsequence, push remaining change lines.
pushDelIns(aLines, aIndex, aLength, bLines, bIndex, bLength, array);
return array.length === 0 ? '' : array.join('\n') + '\n';
};
```
## Example of callback functions to format diff lines
Here is simplified code to format **changed and unchanged lines** in expected and received values after a test fails in Jest:
```js
// Format diff with minus or plus for change lines and space for common lines.
const formatDiffLines = (a, b) => {
// Jest depends on pretty-format package to serialize objects as strings.
// Unindented for comparison to avoid distracting differences:
const aLinesUn = format(a, {indent: 0 /*, other options*/}).split('\n');
const bLinesUn = format(b, {indent: 0 /*, other options*/}).split('\n');
// Indented to display changed and unchanged lines:
const aLinesIn = format(a, {indent: 2 /*, other options*/}).split('\n');
const bLinesIn = format(b, {indent: 2 /*, other options*/}).split('\n');
const aLength = aLinesIn.length; // Validate: aLinesUn.length === aLength
const bLength = bLinesIn.length; // Validate: bLinesUn.length === bLength
const isCommon = (aIndex, bIndex) => aLinesUn[aIndex] === bLinesUn[bIndex];
// Only because the GitHub Flavored Markdown doc collapses adjacent spaces,
// this example code and the following table represent spaces as middle dots.
let aIndex = 0;
let bIndex = 0;
const array = [];
const foundSubsequence = (nCommon, aCommon, bCommon) => {
for (; aIndex !== aCommon; aIndex += 1) {
array.push('' + aLinesIn[aIndex]); // delete is minus
}
for (; bIndex !== bCommon; bIndex += 1) {
array.push('' + bLinesIn[bIndex]); // insert is plus
}
for (; nCommon !== 0; nCommon -= 1, aIndex += 1, bIndex += 1) {
// For common lines, received indentation seems more intuitive.
array.push('··' + bLinesIn[bIndex]); // common is space
}
};
diff(aLength, bLength, isCommon, foundSubsequence);
// After the last common subsequence, push remaining change lines.
for (; aIndex !== aLength; aIndex += 1) {
array.push('' + aLinesIn[aIndex]);
}
for (; bIndex !== bLength; bIndex += 1) {
array.push('' + bLinesIn[bIndex]);
}
return array;
};
const expected = {
searching: '',
sorting: {
ascending: true,
fieldKey: 'what',
},
};
const received = {
searching: '',
sorting: [
{
descending: false,
fieldKey: 'what',
},
],
};
const diffLines = formatDiffLines(expected, received);
```
If N is the sum of lengths of sequences and L is length of a longest common subsequence, then N – L is length of an array of diff lines. In this example, N is 7 + 9, L is 5, and N – L is 11.
| `i` | `diffLines[i]` | `aIndex` | `bIndex` |
| ---: | :--------------------------------- | -------: | -------: |
| `0` | `'··Object {'` | `0` | `0` |
| `1` | `'····"searching": "",'` | `1` | `1` |
| `2` | `'-···"sorting": Object {'` | `2` | |
| `3` | `'-·····"ascending": true,'` | `3` | |
| `4` | `'+·····"sorting": Array ['` | | `2` |
| `5` | `'+·······Object {'` | | `3` |
| `6` | `'+·········"descending": false,'` | | `4` |
| `7` | `'··········"fieldKey": "what",'` | `4` | `5` |
| `8` | `'········},'` | `5` | `6` |
| `9` | `'+·····],'` | | `7` |
| `10` | `'··}'` | `6` | `8` |
## Example of callback functions to find diff items
Here is simplified code to find changed and unchanged substrings **within adjacent changed lines** in expected and received values after a test fails in Jest:
```js
// Return diff items for strings (compatible with diff-match-patch package).
const findDiffItems = (a, b) => {
const isCommon = (aIndex, bIndex) => a[aIndex] === b[bIndex];
let aIndex = 0;
let bIndex = 0;
const array = [];
const foundSubsequence = (nCommon, aCommon, bCommon) => {
if (aIndex !== aCommon) {
array.push([-1, a.slice(aIndex, aCommon)]); // delete is -1
}
if (bIndex !== bCommon) {
array.push([1, b.slice(bIndex, bCommon)]); // insert is 1
}
aIndex = aCommon + nCommon; // number of characters compared in a
bIndex = bCommon + nCommon; // number of characters compared in b
array.push([0, a.slice(aCommon, aIndex)]); // common is 0
};
diff(a.length, b.length, isCommon, foundSubsequence);
// After the last common subsequence, push remaining change items.
if (aIndex !== a.length) {
array.push([-1, a.slice(aIndex)]);
}
if (bIndex !== b.length) {
array.push([1, b.slice(bIndex)]);
}
return array;
};
const expectedDeleted = ['"sorting": Object {', '"ascending": true,'].join(
'\n',
);
const receivedInserted = [
'"sorting": Array [',
'Object {',
'"descending": false,',
].join('\n');
const diffItems = findDiffItems(expectedDeleted, receivedInserted);
```
| `i` | `diffItems[i][0]` | `diffItems[i][1]` |
| --: | ----------------: | :---------------- |
| `0` | `0` | `'"sorting": '` |
| `1` | `1` | `'Array [\n'` |
| `2` | `0` | `'Object {\n"'` |
| `3` | `-1` | `'a'` |
| `4` | `1` | `'de'` |
| `5` | `0` | `'scending": '` |
| `6` | `-1` | `'tru'` |
| `7` | `1` | `'fals'` |
| `8` | `0` | `'e,'` |
The length difference `b.length - a.length` is equal to the sum of `diffItems[i][0]` values times `diffItems[i][1]` lengths. In this example, the difference `48 - 38` is equal to the sum `10`.
| category of diff item | `[0]` | `[1]` lengths | subtotal |
| :-------------------- | ----: | -----------------: | -------: |
| in common | `0` | `11 + 10 + 11 + 2` | `0` |
| to delete from `a` | `–1` | `1 + 3` | `-4` |
| to insert from `b` | `1` | `8 + 2 + 4` | `14` |
Instead of formatting the changed substrings with escape codes for colors in the `foundSubsequence` function to save memory, this example spends memory to **gain flexibility** before formatting, so a separate heuristic algorithm might modify the generic array of diff items to show changes more clearly:
| `i` | `diffItems[i][0]` | `diffItems[i][1]` |
| --: | ----------------: | :---------------- |
| `6` | `-1` | `'true'` |
| `7` | `1` | `'false'` |
| `8` | `0` | `','` |
For expected and received strings of serialized data, the result of finding changed **lines**, and then finding changed **substrings** within adjacent changed lines (as in the preceding two examples) sometimes displays the changes in a more intuitive way than the result of finding changed substrings, and then splitting them into changed and unchanged lines.
/**
* Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*
*/
declare type IsCommon = (aIndex: number, // caller can assume: 0 <= aIndex && aIndex < aLength
bIndex: number) => boolean;
declare type FoundSubsequence = (nCommon: number, // caller can assume: 0 < nCommon
aCommon: number, // caller can assume: 0 <= aCommon && aCommon < aLength
bCommon: number) => void;
export declare type Callbacks = {
foundSubsequence: FoundSubsequence;
isCommon: IsCommon;
};
declare const _default: (aLength: number, bLength: number, isCommon: IsCommon, foundSubsequence: FoundSubsequence) => void;
export default _default;
'use strict';
Object.defineProperty(exports, '__esModule', {
value: true
});
exports.default = void 0;
/**
* Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*
*/
// This diff-sequences package implements the linear space variation in
// An O(ND) Difference Algorithm and Its Variations by Eugene W. Myers
// Relationship in notation between Myers paper and this package:
// A is a
// N is aLength, aEnd - aStart, and so on
// x is aIndex, aFirst, aLast, and so on
// B is b
// M is bLength, bEnd - bStart, and so on
// y is bIndex, bFirst, bLast, and so on
// Δ = N - M is negative of baDeltaLength = bLength - aLength
// D is d
// k is kF
// k + Δ is kF = kR - baDeltaLength
// V is aIndexesF or aIndexesR (see comment below about Indexes type)
// index intervals [1, N] and [1, M] are [0, aLength) and [0, bLength)
// starting point in forward direction (0, 0) is (-1, -1)
// starting point in reverse direction (N + 1, M + 1) is (aLength, bLength)
// The “edit graph” for sequences a and b corresponds to items:
// in a on the horizontal axis
// in b on the vertical axis
//
// Given a-coordinate of a point in a diagonal, you can compute b-coordinate.
//
// Forward diagonals kF:
// zero diagonal intersects top left corner
// positive diagonals intersect top edge
// negative diagonals insersect left edge
//
// Reverse diagonals kR:
// zero diagonal intersects bottom right corner
// positive diagonals intersect right edge
// negative diagonals intersect bottom edge
// The graph contains a directed acyclic graph of edges:
// horizontal: delete an item from a
// vertical: insert an item from b
// diagonal: common item in a and b
//
// The algorithm solves dual problems in the graph analogy:
// Find longest common subsequence: path with maximum number of diagonal edges
// Find shortest edit script: path with minimum number of non-diagonal edges
// Input callback function compares items at indexes in the sequences.
// Output callback function receives the number of adjacent items
// and starting indexes of each common subsequence.
// Either original functions or wrapped to swap indexes if graph is transposed.
// Indexes in sequence a of last point of forward or reverse paths in graph.
// Myers algorithm indexes by diagonal k which for negative is bad deopt in V8.
// This package indexes by iF and iR which are greater than or equal to zero.
// and also updates the index arrays in place to cut memory in half.
// kF = 2 * iF - d
// kR = d - 2 * iR
// Division of index intervals in sequences a and b at the middle change.
// Invariant: intervals do not have common items at the start or end.
const pkg = 'diff-sequences'; // for error messages
const NOT_YET_SET = 0; // small int instead of undefined to avoid deopt in V8
// Return the number of common items that follow in forward direction.
// The length of what Myers paper calls a “snake” in a forward path.
const countCommonItemsF = (aIndex, aEnd, bIndex, bEnd, isCommon) => {
let nCommon = 0;
while (aIndex < aEnd && bIndex < bEnd && isCommon(aIndex, bIndex)) {
aIndex += 1;
bIndex += 1;
nCommon += 1;
}
return nCommon;
}; // Return the number of common items that precede in reverse direction.
// The length of what Myers paper calls a “snake” in a reverse path.
const countCommonItemsR = (aStart, aIndex, bStart, bIndex, isCommon) => {
let nCommon = 0;
while (aStart <= aIndex && bStart <= bIndex && isCommon(aIndex, bIndex)) {
aIndex -= 1;
bIndex -= 1;
nCommon += 1;
}
return nCommon;
}; // A simple function to extend forward paths from (d - 1) to d changes
// when forward and reverse paths cannot yet overlap.
const extendPathsF = (d, aEnd, bEnd, bF, isCommon, aIndexesF, iMaxF) => {
// Unroll the first iteration.
let iF = 0;
let kF = -d; // kF = 2 * iF - d
let aFirst = aIndexesF[iF]; // in first iteration always insert
let aIndexPrev1 = aFirst; // prev value of [iF - 1] in next iteration
aIndexesF[iF] += countCommonItemsF(
aFirst + 1,
aEnd,
bF + aFirst - kF + 1,
bEnd,
isCommon
); // Optimization: skip diagonals in which paths cannot ever overlap.
const nF = d < iMaxF ? d : iMaxF; // The diagonals kF are odd when d is odd and even when d is even.
for (iF += 1, kF += 2; iF <= nF; iF += 1, kF += 2) {
// To get first point of path segment, move one change in forward direction
// from last point of previous path segment in an adjacent diagonal.
// In last possible iteration when iF === d and kF === d always delete.
if (iF !== d && aIndexPrev1 < aIndexesF[iF]) {
aFirst = aIndexesF[iF]; // vertical to insert from b
} else {
aFirst = aIndexPrev1 + 1; // horizontal to delete from a
if (aEnd <= aFirst) {
// Optimization: delete moved past right of graph.
return iF - 1;
}
} // To get last point of path segment, move along diagonal of common items.
aIndexPrev1 = aIndexesF[iF];
aIndexesF[iF] =
aFirst +
countCommonItemsF(aFirst + 1, aEnd, bF + aFirst - kF + 1, bEnd, isCommon);
}
return iMaxF;
}; // A simple function to extend reverse paths from (d - 1) to d changes
// when reverse and forward paths cannot yet overlap.
const extendPathsR = (d, aStart, bStart, bR, isCommon, aIndexesR, iMaxR) => {
// Unroll the first iteration.
let iR = 0;
let kR = d; // kR = d - 2 * iR
let aFirst = aIndexesR[iR]; // in first iteration always insert
let aIndexPrev1 = aFirst; // prev value of [iR - 1] in next iteration
aIndexesR[iR] -= countCommonItemsR(
aStart,
aFirst - 1,
bStart,
bR + aFirst - kR - 1,
isCommon
); // Optimization: skip diagonals in which paths cannot ever overlap.
const nR = d < iMaxR ? d : iMaxR; // The diagonals kR are odd when d is odd and even when d is even.
for (iR += 1, kR -= 2; iR <= nR; iR += 1, kR -= 2) {
// To get first point of path segment, move one change in reverse direction
// from last point of previous path segment in an adjacent diagonal.
// In last possible iteration when iR === d and kR === -d always delete.
if (iR !== d && aIndexesR[iR] < aIndexPrev1) {
aFirst = aIndexesR[iR]; // vertical to insert from b
} else {
aFirst = aIndexPrev1 - 1; // horizontal to delete from a
if (aFirst < aStart) {
// Optimization: delete moved past left of graph.
return iR - 1;
}
} // To get last point of path segment, move along diagonal of common items.
aIndexPrev1 = aIndexesR[iR];
aIndexesR[iR] =
aFirst -
countCommonItemsR(
aStart,
aFirst - 1,
bStart,
bR + aFirst - kR - 1,
isCommon
);
}
return iMaxR;
}; // A complete function to extend forward paths from (d - 1) to d changes.
// Return true if a path overlaps reverse path of (d - 1) changes in its diagonal.
const extendOverlappablePathsF = (
d,
aStart,
aEnd,
bStart,
bEnd,
isCommon,
aIndexesF,
iMaxF,
aIndexesR,
iMaxR,
division
) => {
const bF = bStart - aStart; // bIndex = bF + aIndex - kF
const aLength = aEnd - aStart;
const bLength = bEnd - bStart;
const baDeltaLength = bLength - aLength; // kF = kR - baDeltaLength
// Range of diagonals in which forward and reverse paths might overlap.
const kMinOverlapF = -baDeltaLength - (d - 1); // -(d - 1) <= kR
const kMaxOverlapF = -baDeltaLength + (d - 1); // kR <= (d - 1)
let aIndexPrev1 = NOT_YET_SET; // prev value of [iF - 1] in next iteration
// Optimization: skip diagonals in which paths cannot ever overlap.
const nF = d < iMaxF ? d : iMaxF; // The diagonals kF = 2 * iF - d are odd when d is odd and even when d is even.
for (let iF = 0, kF = -d; iF <= nF; iF += 1, kF += 2) {
// To get first point of path segment, move one change in forward direction
// from last point of previous path segment in an adjacent diagonal.
// In first iteration when iF === 0 and kF === -d always insert.
// In last possible iteration when iF === d and kF === d always delete.
const insert = iF === 0 || (iF !== d && aIndexPrev1 < aIndexesF[iF]);
const aLastPrev = insert ? aIndexesF[iF] : aIndexPrev1;
const aFirst = insert
? aLastPrev // vertical to insert from b
: aLastPrev + 1; // horizontal to delete from a
// To get last point of path segment, move along diagonal of common items.
const bFirst = bF + aFirst - kF;
const nCommonF = countCommonItemsF(
aFirst + 1,
aEnd,
bFirst + 1,
bEnd,
isCommon
);
const aLast = aFirst + nCommonF;
aIndexPrev1 = aIndexesF[iF];
aIndexesF[iF] = aLast;
if (kMinOverlapF <= kF && kF <= kMaxOverlapF) {
// Solve for iR of reverse path with (d - 1) changes in diagonal kF:
// kR = kF + baDeltaLength
// kR = (d - 1) - 2 * iR
const iR = (d - 1 - (kF + baDeltaLength)) / 2; // If this forward path overlaps the reverse path in this diagonal,
// then this is the middle change of the index intervals.
if (iR <= iMaxR && aIndexesR[iR] - 1 <= aLast) {
// Unlike the Myers algorithm which finds only the middle “snake”
// this package can find two common subsequences per division.
// Last point of previous path segment is on an adjacent diagonal.
const bLastPrev = bF + aLastPrev - (insert ? kF + 1 : kF - 1); // Because of invariant that intervals preceding the middle change
// cannot have common items at the end,
// move in reverse direction along a diagonal of common items.
const nCommonR = countCommonItemsR(
aStart,
aLastPrev,
bStart,
bLastPrev,
isCommon
);
const aIndexPrevFirst = aLastPrev - nCommonR;
const bIndexPrevFirst = bLastPrev - nCommonR;
const aEndPreceding = aIndexPrevFirst + 1;
const bEndPreceding = bIndexPrevFirst + 1;
division.nChangePreceding = d - 1;
if (d - 1 === aEndPreceding + bEndPreceding - aStart - bStart) {
// Optimization: number of preceding changes in forward direction
// is equal to number of items in preceding interval,
// therefore it cannot contain any common items.
division.aEndPreceding = aStart;
division.bEndPreceding = bStart;
} else {
division.aEndPreceding = aEndPreceding;
division.bEndPreceding = bEndPreceding;
}
division.nCommonPreceding = nCommonR;
if (nCommonR !== 0) {
division.aCommonPreceding = aEndPreceding;
division.bCommonPreceding = bEndPreceding;
}
division.nCommonFollowing = nCommonF;
if (nCommonF !== 0) {
division.aCommonFollowing = aFirst + 1;
division.bCommonFollowing = bFirst + 1;
}
const aStartFollowing = aLast + 1;
const bStartFollowing = bFirst + nCommonF + 1;
division.nChangeFollowing = d - 1;
if (d - 1 === aEnd + bEnd - aStartFollowing - bStartFollowing) {
// Optimization: number of changes in reverse direction
// is equal to number of items in following interval,
// therefore it cannot contain any common items.
division.aStartFollowing = aEnd;
division.bStartFollowing = bEnd;
} else {
division.aStartFollowing = aStartFollowing;
division.bStartFollowing = bStartFollowing;
}
return true;
}
}
}
return false;
}; // A complete function to extend reverse paths from (d - 1) to d changes.
// Return true if a path overlaps forward path of d changes in its diagonal.
const extendOverlappablePathsR = (
d,
aStart,
aEnd,
bStart,
bEnd,
isCommon,
aIndexesF,
iMaxF,
aIndexesR,
iMaxR,
division
) => {
const bR = bEnd - aEnd; // bIndex = bR + aIndex - kR
const aLength = aEnd - aStart;
const bLength = bEnd - bStart;
const baDeltaLength = bLength - aLength; // kR = kF + baDeltaLength
// Range of diagonals in which forward and reverse paths might overlap.
const kMinOverlapR = baDeltaLength - d; // -d <= kF
const kMaxOverlapR = baDeltaLength + d; // kF <= d
let aIndexPrev1 = NOT_YET_SET; // prev value of [iR - 1] in next iteration
// Optimization: skip diagonals in which paths cannot ever overlap.
const nR = d < iMaxR ? d : iMaxR; // The diagonals kR = d - 2 * iR are odd when d is odd and even when d is even.
for (let iR = 0, kR = d; iR <= nR; iR += 1, kR -= 2) {
// To get first point of path segment, move one change in reverse direction
// from last point of previous path segment in an adjacent diagonal.
// In first iteration when iR === 0 and kR === d always insert.
// In last possible iteration when iR === d and kR === -d always delete.
const insert = iR === 0 || (iR !== d && aIndexesR[iR] < aIndexPrev1);
const aLastPrev = insert ? aIndexesR[iR] : aIndexPrev1;
const aFirst = insert
? aLastPrev // vertical to insert from b
: aLastPrev - 1; // horizontal to delete from a
// To get last point of path segment, move along diagonal of common items.
const bFirst = bR + aFirst - kR;
const nCommonR = countCommonItemsR(
aStart,
aFirst - 1,
bStart,
bFirst - 1,
isCommon
);
const aLast = aFirst - nCommonR;
aIndexPrev1 = aIndexesR[iR];
aIndexesR[iR] = aLast;
if (kMinOverlapR <= kR && kR <= kMaxOverlapR) {
// Solve for iF of forward path with d changes in diagonal kR:
// kF = kR - baDeltaLength
// kF = 2 * iF - d
const iF = (d + (kR - baDeltaLength)) / 2; // If this reverse path overlaps the forward path in this diagonal,
// then this is a middle change of the index intervals.
if (iF <= iMaxF && aLast - 1 <= aIndexesF[iF]) {
const bLast = bFirst - nCommonR;
division.nChangePreceding = d;
if (d === aLast + bLast - aStart - bStart) {
// Optimization: number of changes in reverse direction
// is equal to number of items in preceding interval,
// therefore it cannot contain any common items.
division.aEndPreceding = aStart;
division.bEndPreceding = bStart;
} else {
division.aEndPreceding = aLast;
division.bEndPreceding = bLast;
}
division.nCommonPreceding = nCommonR;
if (nCommonR !== 0) {
// The last point of reverse path segment is start of common subsequence.
division.aCommonPreceding = aLast;
division.bCommonPreceding = bLast;
}
division.nChangeFollowing = d - 1;
if (d === 1) {
// There is no previous path segment.
division.nCommonFollowing = 0;
division.aStartFollowing = aEnd;
division.bStartFollowing = bEnd;
} else {
// Unlike the Myers algorithm which finds only the middle “snake”
// this package can find two common subsequences per division.
// Last point of previous path segment is on an adjacent diagonal.
const bLastPrev = bR + aLastPrev - (insert ? kR - 1 : kR + 1); // Because of invariant that intervals following the middle change
// cannot have common items at the start,
// move in forward direction along a diagonal of common items.
const nCommonF = countCommonItemsF(
aLastPrev,
aEnd,
bLastPrev,
bEnd,
isCommon
);
division.nCommonFollowing = nCommonF;
if (nCommonF !== 0) {
// The last point of reverse path segment is start of common subsequence.
division.aCommonFollowing = aLastPrev;
division.bCommonFollowing = bLastPrev;
}
const aStartFollowing = aLastPrev + nCommonF; // aFirstPrev
const bStartFollowing = bLastPrev + nCommonF; // bFirstPrev
if (d - 1 === aEnd + bEnd - aStartFollowing - bStartFollowing) {
// Optimization: number of changes in forward direction
// is equal to number of items in following interval,
// therefore it cannot contain any common items.
division.aStartFollowing = aEnd;
division.bStartFollowing = bEnd;
} else {
division.aStartFollowing = aStartFollowing;
division.bStartFollowing = bStartFollowing;
}
}
return true;
}
}
}
return false;
}; // Given index intervals and input function to compare items at indexes,
// divide at the middle change.
//
// DO NOT CALL if start === end, because interval cannot contain common items
// and because this function will throw the “no overlap” error.
const divide = (
nChange,
aStart,
aEnd,
bStart,
bEnd,
isCommon,
aIndexesF,
aIndexesR,
division // output
) => {
const bF = bStart - aStart; // bIndex = bF + aIndex - kF
const bR = bEnd - aEnd; // bIndex = bR + aIndex - kR
const aLength = aEnd - aStart;
const bLength = bEnd - bStart; // Because graph has square or portrait orientation,
// length difference is minimum number of items to insert from b.
// Corresponding forward and reverse diagonals in graph
// depend on length difference of the sequences:
// kF = kR - baDeltaLength
// kR = kF + baDeltaLength
const baDeltaLength = bLength - aLength; // Optimization: max diagonal in graph intersects corner of shorter side.
let iMaxF = aLength;
let iMaxR = aLength; // Initialize no changes yet in forward or reverse direction:
aIndexesF[0] = aStart - 1; // at open start of interval, outside closed start
aIndexesR[0] = aEnd; // at open end of interval
if (baDeltaLength % 2 === 0) {
// The number of changes in paths is 2 * d if length difference is even.
const dMin = (nChange || baDeltaLength) / 2;
const dMax = (aLength + bLength) / 2;
for (let d = 1; d <= dMax; d += 1) {
iMaxF = extendPathsF(d, aEnd, bEnd, bF, isCommon, aIndexesF, iMaxF);
if (d < dMin) {
iMaxR = extendPathsR(d, aStart, bStart, bR, isCommon, aIndexesR, iMaxR);
} else if (
// If a reverse path overlaps a forward path in the same diagonal,
// return a division of the index intervals at the middle change.
extendOverlappablePathsR(
d,
aStart,
aEnd,
bStart,
bEnd,
isCommon,
aIndexesF,
iMaxF,
aIndexesR,
iMaxR,
division
)
) {
return;
}
}
} else {
// The number of changes in paths is 2 * d - 1 if length difference is odd.
const dMin = ((nChange || baDeltaLength) + 1) / 2;
const dMax = (aLength + bLength + 1) / 2; // Unroll first half iteration so loop extends the relevant pairs of paths.
// Because of invariant that intervals have no common items at start or end,
// and limitation not to call divide with empty intervals,
// therefore it cannot be called if a forward path with one change
// would overlap a reverse path with no changes, even if dMin === 1.
let d = 1;
iMaxF = extendPathsF(d, aEnd, bEnd, bF, isCommon, aIndexesF, iMaxF);
for (d += 1; d <= dMax; d += 1) {
iMaxR = extendPathsR(
d - 1,
aStart,
bStart,
bR,
isCommon,
aIndexesR,
iMaxR
);
if (d < dMin) {
iMaxF = extendPathsF(d, aEnd, bEnd, bF, isCommon, aIndexesF, iMaxF);
} else if (
// If a forward path overlaps a reverse path in the same diagonal,
// return a division of the index intervals at the middle change.
extendOverlappablePathsF(
d,
aStart,
aEnd,
bStart,
bEnd,
isCommon,
aIndexesF,
iMaxF,
aIndexesR,
iMaxR,
division
)
) {
return;
}
}
}
/* istanbul ignore next */
throw new Error(
`${pkg}: no overlap aStart=${aStart} aEnd=${aEnd} bStart=${bStart} bEnd=${bEnd}`
);
}; // Given index intervals and input function to compare items at indexes,
// return by output function the number of adjacent items and starting indexes
// of each common subsequence. Divide and conquer with only linear space.
//
// The index intervals are half open [start, end) like array slice method.
// DO NOT CALL if start === end, because interval cannot contain common items
// and because divide function will throw the “no overlap” error.
const findSubsequences = (
nChange,
aStart,
aEnd,
bStart,
bEnd,
transposed,
callbacks,
aIndexesF,
aIndexesR,
division // temporary memory, not input nor output
) => {
if (bEnd - bStart < aEnd - aStart) {
// Transpose graph so it has portrait instead of landscape orientation.
// Always compare shorter to longer sequence for consistency and optimization.
transposed = !transposed;
if (transposed && callbacks.length === 1) {
// Lazily wrap callback functions to swap args if graph is transposed.
const {foundSubsequence, isCommon} = callbacks[0];
callbacks[1] = {
foundSubsequence: (nCommon, bCommon, aCommon) => {
foundSubsequence(nCommon, aCommon, bCommon);
},
isCommon: (bIndex, aIndex) => isCommon(aIndex, bIndex)
};
}
const tStart = aStart;
const tEnd = aEnd;
aStart = bStart;
aEnd = bEnd;
bStart = tStart;
bEnd = tEnd;
}
const {foundSubsequence, isCommon} = callbacks[transposed ? 1 : 0]; // Divide the index intervals at the middle change.
divide(
nChange,
aStart,
aEnd,
bStart,
bEnd,
isCommon,
aIndexesF,
aIndexesR,
division
);
const {
nChangePreceding,
aEndPreceding,
bEndPreceding,
nCommonPreceding,
aCommonPreceding,
bCommonPreceding,
nCommonFollowing,
aCommonFollowing,
bCommonFollowing,
nChangeFollowing,
aStartFollowing,
bStartFollowing
} = division; // Unless either index interval is empty, they might contain common items.
if (aStart < aEndPreceding && bStart < bEndPreceding) {
// Recursely find and return common subsequences preceding the division.
findSubsequences(
nChangePreceding,
aStart,
aEndPreceding,
bStart,
bEndPreceding,
transposed,
callbacks,
aIndexesF,
aIndexesR,
division
);
} // Return common subsequences that are adjacent to the middle change.
if (nCommonPreceding !== 0) {
foundSubsequence(nCommonPreceding, aCommonPreceding, bCommonPreceding);
}
if (nCommonFollowing !== 0) {
foundSubsequence(nCommonFollowing, aCommonFollowing, bCommonFollowing);
} // Unless either index interval is empty, they might contain common items.
if (aStartFollowing < aEnd && bStartFollowing < bEnd) {
// Recursely find and return common subsequences following the division.
findSubsequences(
nChangeFollowing,
aStartFollowing,
aEnd,
bStartFollowing,
bEnd,
transposed,
callbacks,
aIndexesF,
aIndexesR,
division
);
}
};
const validateLength = (name, arg) => {
if (typeof arg !== 'number') {
throw new TypeError(`${pkg}: ${name} typeof ${typeof arg} is not a number`);
}
if (!Number.isSafeInteger(arg)) {
throw new RangeError(`${pkg}: ${name} value ${arg} is not a safe integer`);
}
if (arg < 0) {
throw new RangeError(`${pkg}: ${name} value ${arg} is a negative integer`);
}
};
const validateCallback = (name, arg) => {
const type = typeof arg;
if (type !== 'function') {
throw new TypeError(`${pkg}: ${name} typeof ${type} is not a function`);
}
}; // Compare items in two sequences to find a longest common subsequence.
// Given lengths of sequences and input function to compare items at indexes,
// return by output function the number of adjacent items and starting indexes
// of each common subsequence.
var _default = (aLength, bLength, isCommon, foundSubsequence) => {
validateLength('aLength', aLength);
validateLength('bLength', bLength);
validateCallback('isCommon', isCommon);
validateCallback('foundSubsequence', foundSubsequence); // Count common items from the start in the forward direction.
const nCommonF = countCommonItemsF(0, aLength, 0, bLength, isCommon);
if (nCommonF !== 0) {
foundSubsequence(nCommonF, 0, 0);
} // Unless both sequences consist of common items only,
// find common items in the half-trimmed index intervals.
if (aLength !== nCommonF || bLength !== nCommonF) {
// Invariant: intervals do not have common items at the start.
// The start of an index interval is closed like array slice method.
const aStart = nCommonF;
const bStart = nCommonF; // Count common items from the end in the reverse direction.
const nCommonR = countCommonItemsR(
aStart,
aLength - 1,
bStart,
bLength - 1,
isCommon
); // Invariant: intervals do not have common items at the end.
// The end of an index interval is open like array slice method.
const aEnd = aLength - nCommonR;
const bEnd = bLength - nCommonR; // Unless one sequence consists of common items only,
// therefore the other trimmed index interval consists of changes only,
// find common items in the trimmed index intervals.
const nCommonFR = nCommonF + nCommonR;
if (aLength !== nCommonFR && bLength !== nCommonFR) {
const nChange = 0; // number of change items is not yet known
const transposed = false; // call the original unwrapped functions
const callbacks = [
{
foundSubsequence,
isCommon
}
]; // Indexes in sequence a of last points in furthest reaching paths
// from outside the start at top left in the forward direction:
const aIndexesF = [NOT_YET_SET]; // from the end at bottom right in the reverse direction:
const aIndexesR = [NOT_YET_SET]; // Initialize one object as output of all calls to divide function.
const division = {
aCommonFollowing: NOT_YET_SET,
aCommonPreceding: NOT_YET_SET,
aEndPreceding: NOT_YET_SET,
aStartFollowing: NOT_YET_SET,
bCommonFollowing: NOT_YET_SET,
bCommonPreceding: NOT_YET_SET,
bEndPreceding: NOT_YET_SET,
bStartFollowing: NOT_YET_SET,
nChangeFollowing: NOT_YET_SET,
nChangePreceding: NOT_YET_SET,
nCommonFollowing: NOT_YET_SET,
nCommonPreceding: NOT_YET_SET
}; // Find and return common subsequences in the trimmed index intervals.
findSubsequences(
nChange,
aStart,
aEnd,
bStart,
bEnd,
transposed,
callbacks,
aIndexesF,
aIndexesR,
division
);
}
if (nCommonR !== 0) {
foundSubsequence(nCommonR, aEnd, bEnd);
}
}
};
exports.default = _default;
{
"name": "diff-sequences",
"version": "26.6.2",
"repository": {
"type": "git",
"url": "https://github.com/facebook/jest.git",
"directory": "packages/diff-sequences"
},
"license": "MIT",
"description": "Compare items in two sequences to find a longest common subsequence",
"keywords": [
"fast",
"linear",
"space",
"callback",
"diff"
],
"engines": {
"node": ">= 10.14.2"
},
"main": "build/index.js",
"types": "build/index.d.ts",
"scripts": {
"perf": "node --expose-gc perf/index.js"
},
"devDependencies": {
"benchmark": "^2.1.4",
"diff": "^4.0.1",
"fast-check": "^2.0.0"
},
"publishConfig": {
"access": "public"
},
"gitHead": "4c46930615602cbf983fb7e8e82884c282a624d5"
}
## Benchmark time for `diff-sequences` versus `diff`
A ratio less than 1.0 means `diff-sequences` is faster.
### n = 20
| name | % | ratio | improved | rme | baseline | rme |
| :----- | ---: | :----- | :-------- | ----: | :-------- | ----: |
| delete | 20% | 0.1824 | 3.0639e-6 | 1.11% | 1.6795e-5 | 0.78% |
| insert | 20% | 0.1367 | 2.5786e-6 | 0.75% | 1.8866e-5 | 0.85% |
| delete | 40% | 0.1015 | 3.0534e-6 | 1.00% | 3.0090e-5 | 0.70% |
| insert | 40% | 0.0791 | 2.6722e-6 | 0.61% | 3.3791e-5 | 0.56% |
| delete | 80% | 0.0410 | 2.8870e-6 | 0.93% | 7.0411e-5 | 0.72% |
| insert | 80% | 0.0371 | 2.5786e-6 | 0.83% | 6.9431e-5 | 0.62% |
| change | 10% | 0.1504 | 2.8703e-6 | 0.71% | 1.9087e-5 | 0.83% |
| change | 20% | 0.1706 | 3.2637e-6 | 0.78% | 1.9127e-5 | 0.62% |
| change | 50% | 0.0944 | 1.2012e-5 | 0.55% | 1.2724e-4 | 0.76% |
| change | 100% | 0.0522 | 1.5422e-5 | 0.61% | 2.9566e-4 | 0.66% |
### n = 200
| name | % | ratio | improved | rme | baseline | rme |
| :----- | ---: | :----- | :-------- | ----: | :-------- | ----: |
| delete | 20% | 0.1524 | 7.2866e-5 | 0.75% | 4.7797e-4 | 0.80% |
| insert | 20% | 0.1226 | 6.1561e-5 | 0.58% | 5.0198e-4 | 0.66% |
| delete | 40% | 0.1118 | 1.5674e-4 | 0.67% | 1.4020e-3 | 0.58% |
| insert | 40% | 0.0894 | 1.2906e-4 | 0.64% | 1.4435e-3 | 0.53% |
| delete | 80% | 0.0796 | 3.0119e-4 | 0.58% | 3.7852e-3 | 0.52% |
| insert | 80% | 0.0734 | 2.4713e-4 | 0.67% | 3.3653e-3 | 0.54% |
| change | 10% | 0.1572 | 7.2965e-5 | 0.48% | 4.6426e-4 | 0.73% |
| change | 20% | 0.1446 | 7.0056e-5 | 0.69% | 4.8456e-4 | 0.53% |
| change | 50% | 0.0764 | 6.5638e-4 | 0.67% | 8.5946e-3 | 0.70% |
| change | 100% | 0.0525 | 1.1160e-3 | 0.51% | 2.1249e-2 | 0.63% |
### n = 2000
| name | % | ratio | improved | rme | baseline | rme |
| :----- | ---: | :----- | :-------- | ----: | :-------- | ----: |
| delete | 20% | 0.0669 | 3.4073e-3 | 0.54% | 5.0922e-2 | 0.54% |
| insert | 20% | 0.0588 | 2.8273e-3 | 0.51% | 4.8111e-2 | 0.46% |
| delete | 40% | 0.0517 | 1.1048e-2 | 0.52% | 2.1367e-1 | 0.47% |
| insert | 40% | 0.0460 | 9.1469e-3 | 0.37% | 1.9878e-1 | 0.26% |
| delete | 80% | 0.0563 | 2.7426e-2 | 0.56% | 4.8674e-1 | 0.36% |
| insert | 80% | 0.0506 | 2.2208e-2 | 0.35% | 4.3888e-1 | 0.47% |
| change | 10% | 0.0716 | 3.1267e-3 | 1.21% | 4.3652e-2 | 0.56% |
| change | 20% | 0.0621 | 3.0197e-3 | 0.72% | 4.8652e-2 | 0.45% |
| change | 50% | 0.0083 | 5.4250e-2 | 0.62% | 6.5595e+0 | 3.60% |
| change | 100% | 0.0493 | 1.0534e-1 | 0.71% | 2.1362e+0 | 0.21% |
/**
* Copyright (c) Facebook, Inc. and its affiliates. All Rights Reserved.
*
* This source code is licensed under the MIT license found in the
* LICENSE file in the root directory of this source tree.
*/
// Make sure to run node with --expose-gc option!
// The times are reliable if about 1% relative mean error if you run it:
// * immediately after restart
// * with 100% battery charge
// * not connected to network
/* eslint import/no-extraneous-dependencies: "off" */
const Benchmark = require('benchmark');
const diffBaseline = require('diff').diffLines;
const diffImproved = require('../build/index.js').default;
const testBaseline = (a, b) => {
const benchmark = new Benchmark({
fn() {
diffBaseline(a, b);
},
name: 'baseline',
onCycle() {
global.gc(); // after run cycle
},
onStart() {
global.gc(); // when benchmark starts
},
});
benchmark.run({async: false});
return benchmark.stats;
};
const testImproved = function (a, b) {
const benchmark = new Benchmark({
fn() {
// Split string arguments to make fair comparison with baseline.
const aItems = a.split('\n');
const bItems = b.split('\n');
const isCommon = (aIndex, bIndex) => aItems[aIndex] === bItems[bIndex];
// This callback obviously does less than baseline `diff` package,
// but avoiding double work and memory churn is the goal.
// For example, `jest-diff` has had to split strings that `diff` joins.
const foundSubsequence = () => {};
diffImproved(aItems.length, bItems.length, isCommon, foundSubsequence);
},
name: 'improved',
onCycle() {
global.gc(); // after run cycle
},
onStart() {
global.gc(); // when benchmark starts
},
});
benchmark.run({async: false});
return benchmark.stats;
};
const writeHeading2 = () => {
console.log('## Benchmark time for `diff-sequences` versus `diff`\n');
console.log('A ratio less than 1.0 means `diff-sequences` is faster.');
};
const writeHeading3 = n => {
console.log(`\n### n = ${n}\n`);
console.log('| name | % | ratio | improved | rme | baseline | rme |');
console.log('| :--- | ---: | :--- | :--- | ---: | :--- | ---: |');
};
const writeRow = (name, percent, statsImproved, statsBaseline) => {
const {mean: meanImproved, rme: rmeImproved} = statsImproved;
const {mean: meanBaseline, rme: rmeBaseline} = statsBaseline;
const ratio = meanImproved / meanBaseline;
console.log(
`| ${name} | ${percent}% | ${ratio.toFixed(
4,
)} | ${meanImproved.toExponential(4)} | ${rmeImproved.toFixed(
2,
)}% | ${meanBaseline.toExponential(4)} | ${rmeBaseline.toFixed(2)}% |`,
);
};
const testDeleteInsert = (tenths, more, less) => {
// For improved `diff-sequences` package, delete is often slower than insert.
const statsDeleteImproved = testImproved(more, less);
const statsDeleteBaseline = testBaseline(more, less);
writeRow('delete', tenths * 10, statsDeleteImproved, statsDeleteBaseline);
// For baseline `diff` package, many insertions is serious perf problem.
// However, the benchmark package cannot accurately measure for large n.
const statsInsertBaseline = testBaseline(less, more);
const statsInsertImproved = testImproved(less, more);
writeRow('insert', tenths * 10, statsInsertImproved, statsInsertBaseline);
};
const testChange = (tenths, expected, received) => {
const statsImproved = testImproved(expected, received);
const statsBaseline = testBaseline(expected, received);
writeRow('change', tenths * 10, statsImproved, statsBaseline);
};
const getItems = (n, callback) => {
const items = [];
for (let i = 0; i !== n; i += 1) {
const item = callback(i);
if (typeof item === 'string') {
items.push(item);
}
}
return items.join('\n');
};
// Simulate change of property name which is usually not same line.
// Expected: 0 1 2 3 4 5 6 7 8 9 and so on
// Received: 1 2 3 4 x0 5 6 7 8 9 and so on
const change2 = i => {
const j = i % 10;
return j === 4 ? `x${i - 4}` : j < 4 ? `${i + 1}` : `${i}`;
};
const testLength = n => {
const all = getItems(n, i => `${i}`);
writeHeading3(n);
[2, 4, 8].forEach(tenth => {
testDeleteInsert(
tenth,
all,
getItems(n, i => i % 10 >= tenth && `${i}`),
);
});
testChange(
1,
all,
getItems(n, i => (i % 10 === 0 ? `x${i}` : `${i}`)),
);
testChange(2, all, getItems(n, change2));
testChange(
5,
all,
getItems(n, i => (i % 2 === 0 ? `x${i}` : `${i}`)),
);
testChange(
10,
all,
getItems(n, i => `x${i}`),
); // simulate TDD
};
writeHeading2();
testLength(20);
testLength(200);
testLength(2000);
/**
Check if [`argv`](https://nodejs.org/docs/latest/api/process.html#process_process_argv) has a specific flag.
@param flag - CLI flag to look for. The `--` prefix is optional.
@param argv - CLI arguments. Default: `process.argv`.
@returns Whether the flag exists.
@example
```
// $ ts-node foo.ts -f --unicorn --foo=bar -- --rainbow
// foo.ts
import hasFlag = require('has-flag');
hasFlag('unicorn');
//=> true
hasFlag('--unicorn');
//=> true
hasFlag('f');
//=> true
hasFlag('-f');
//=> true
hasFlag('foo=bar');
//=> true
hasFlag('foo');
//=> false
hasFlag('rainbow');
//=> false
```
*/
declare function hasFlag(flag: string, argv?: string[]): boolean;
export = hasFlag;
'use strict';
module.exports = (flag, argv = process.argv) => {
const prefix = flag.startsWith('-') ? '' : (flag.length === 1 ? '-' : '--');
const position = argv.indexOf(prefix + flag);
const terminatorPosition = argv.indexOf('--');
return position !== -1 && (terminatorPosition === -1 || position < terminatorPosition);
};
MIT License
Copyright (c) Sindre Sorhus <sindresorhus@gmail.com> (sindresorhus.com)
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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