getAlignedDiffs.js

'use strict';

Object.defineProperty(exports, '__esModule', {
  value: true
});
exports.default = void 0;

var _cleanupSemantic = require('./cleanupSemantic');

function _defineProperty(obj, key, value) {
  if (key in obj) {
    Object.defineProperty(obj, key, {
      value: value,
      enumerable: true,
      configurable: true,
      writable: true
    });
  } else {
    obj[key] = value;
  }
  return obj;
}

// Given change op and array of diffs, return concatenated string:
// * include common strings
// * include change strings which have argument op with changeColor
// * exclude change strings which have opposite op
const concatenateRelevantDiffs = (op, diffs, changeColor) =>
  diffs.reduce(
    (reduced, diff) =>
      reduced +
      (diff[0] === _cleanupSemantic.DIFF_EQUAL
        ? diff[1]
        : diff[0] === op && diff[1].length !== 0 // empty if change is newline
        ? changeColor(diff[1])
        : ''),
    ''
  ); // Encapsulate change lines until either a common newline or the end.

class ChangeBuffer {
  // incomplete line
  // complete lines
  constructor(op, changeColor) {
    _defineProperty(this, 'op', void 0);

    _defineProperty(this, 'line', void 0);

    _defineProperty(this, 'lines', void 0);

    _defineProperty(this, 'changeColor', void 0);

    this.op = op;
    this.line = [];
    this.lines = [];
    this.changeColor = changeColor;
  }

  pushSubstring(substring) {
    this.pushDiff(new _cleanupSemantic.Diff(this.op, substring));
  }

  pushLine() {
    // Assume call only if line has at least one diff,
    // therefore an empty line must have a diff which has an empty string.
    // If line has multiple diffs, then assume it has a common diff,
    // therefore change diffs have change color;
    // otherwise then it has line color only.
    this.lines.push(
      this.line.length !== 1
        ? new _cleanupSemantic.Diff(
            this.op,
            concatenateRelevantDiffs(this.op, this.line, this.changeColor)
          )
        : this.line[0][0] === this.op
        ? this.line[0] // can use instance
        : new _cleanupSemantic.Diff(this.op, this.line[0][1]) // was common diff
    );
    this.line.length = 0;
  }

  isLineEmpty() {
    return this.line.length === 0;
  } // Minor input to buffer.

  pushDiff(diff) {
    this.line.push(diff);
  } // Main input to buffer.

  align(diff) {
    const string = diff[1];

    if (string.includes('\n')) {
      const substrings = string.split('\n');
      const iLast = substrings.length - 1;
      substrings.forEach((substring, i) => {
        if (i < iLast) {
          // The first substring completes the current change line.
          // A middle substring is a change line.
          this.pushSubstring(substring);
          this.pushLine();
        } else if (substring.length !== 0) {
          // The last substring starts a change line, if it is not empty.
          // Important: This non-empty condition also automatically omits
          // the newline appended to the end of expected and received strings.
          this.pushSubstring(substring);
        }
      });
    } else {
      // Append non-multiline string to current change line.
      this.pushDiff(diff);
    }
  } // Output from buffer.

  moveLinesTo(lines) {
    if (!this.isLineEmpty()) {
      this.pushLine();
    }

    lines.push(...this.lines);
    this.lines.length = 0;
  }
} // Encapsulate common and change lines.

class CommonBuffer {
  constructor(deleteBuffer, insertBuffer) {
    _defineProperty(this, 'deleteBuffer', void 0);

    _defineProperty(this, 'insertBuffer', void 0);

    _defineProperty(this, 'lines', void 0);

    this.deleteBuffer = deleteBuffer;
    this.insertBuffer = insertBuffer;
    this.lines = [];
  }

  pushDiffCommonLine(diff) {
    this.lines.push(diff);
  }

  pushDiffChangeLines(diff) {
    const isDiffEmpty = diff[1].length === 0; // An empty diff string is redundant, unless a change line is empty.

    if (!isDiffEmpty || this.deleteBuffer.isLineEmpty()) {
      this.deleteBuffer.pushDiff(diff);
    }

    if (!isDiffEmpty || this.insertBuffer.isLineEmpty()) {
      this.insertBuffer.pushDiff(diff);
    }
  }

  flushChangeLines() {
    this.deleteBuffer.moveLinesTo(this.lines);
    this.insertBuffer.moveLinesTo(this.lines);
  } // Input to buffer.

  align(diff) {
    const op = diff[0];
    const string = diff[1];

    if (string.includes('\n')) {
      const substrings = string.split('\n');
      const iLast = substrings.length - 1;
      substrings.forEach((substring, i) => {
        if (i === 0) {
          const subdiff = new _cleanupSemantic.Diff(op, substring);

          if (
            this.deleteBuffer.isLineEmpty() &&
            this.insertBuffer.isLineEmpty()
          ) {
            // If both current change lines are empty,
            // then the first substring is a common line.
            this.flushChangeLines();
            this.pushDiffCommonLine(subdiff);
          } else {
            // If either current change line is non-empty,
            // then the first substring completes the change lines.
            this.pushDiffChangeLines(subdiff);
            this.flushChangeLines();
          }
        } else if (i < iLast) {
          // A middle substring is a common line.
          this.pushDiffCommonLine(new _cleanupSemantic.Diff(op, substring));
        } else if (substring.length !== 0) {
          // The last substring starts a change line, if it is not empty.
          // Important: This non-empty condition also automatically omits
          // the newline appended to the end of expected and received strings.
          this.pushDiffChangeLines(new _cleanupSemantic.Diff(op, substring));
        }
      });
    } else {
      // Append non-multiline string to current change lines.
      // Important: It cannot be at the end following empty change lines,
      // because newline appended to the end of expected and received strings.
      this.pushDiffChangeLines(diff);
    }
  } // Output from buffer.

  getLines() {
    this.flushChangeLines();
    return this.lines;
  }
} // Given diffs from expected and received strings,
// return new array of diffs split or joined into lines.
//
// To correctly align a change line at the end, the algorithm:
// * assumes that a newline was appended to the strings
// * omits the last newline from the output array
//
// Assume the function is not called:
// * if either expected or received is empty string
// * if neither expected nor received is multiline string

const getAlignedDiffs = (diffs, changeColor) => {
  const deleteBuffer = new ChangeBuffer(
    _cleanupSemantic.DIFF_DELETE,
    changeColor
  );
  const insertBuffer = new ChangeBuffer(
    _cleanupSemantic.DIFF_INSERT,
    changeColor
  );
  const commonBuffer = new CommonBuffer(deleteBuffer, insertBuffer);
  diffs.forEach(diff => {
    switch (diff[0]) {
      case _cleanupSemantic.DIFF_DELETE:
        deleteBuffer.align(diff);
        break;

      case _cleanupSemantic.DIFF_INSERT:
        insertBuffer.align(diff);
        break;

      default:
        commonBuffer.align(diff);
    }
  });
  return commonBuffer.getLines();
};

var _default = getAlignedDiffs;
exports.default = _default;