Function diffLinesUnified2

packages/jest-diff/src/diffLines.ts:114–163

(
  aLinesDisplay: Array<string>,
  bLinesDisplay: Array<string>,
  aLinesCompare: Array<string>,
  bLinesCompare: Array<string>,
  options?: DiffOptions,
)

// Compare the pair of comparison arrays line-by-line.
// Format the corresponding lines in the pair of displayable arrays.
export const diffLinesUnified2 = (
  aLinesDisplay: Array<string>,
  bLinesDisplay: Array<string>,
  aLinesCompare: Array<string>,
  bLinesCompare: Array<string>,
  options?: DiffOptions,
): string => {
  if (isEmptyString(aLinesDisplay) && isEmptyString(aLinesCompare)) {
    aLinesDisplay = [];
    aLinesCompare = [];
  }
  if (isEmptyString(bLinesDisplay) && isEmptyString(bLinesCompare)) {
    bLinesDisplay = [];
    bLinesCompare = [];
  }

  if (
    aLinesDisplay.length !== aLinesCompare.length ||
    bLinesDisplay.length !== bLinesCompare.length
  ) {
    // Fall back to diff of display lines.
    return diffLinesUnified(aLinesDisplay, bLinesDisplay, options);
  }

  const diffs = diffLinesRaw(aLinesCompare, bLinesCompare);

  // Replace comparison lines with displayable lines.
  let aIndex = 0;
  let bIndex = 0;
  for (const diff of diffs) {
    switch (diff[0]) {
      case DIFF_DELETE:
        diff[1] = aLinesDisplay[aIndex];
        aIndex += 1;
        break;

      case DIFF_INSERT:
        diff[1] = bLinesDisplay[bIndex];
        bIndex += 1;
        break;

      default:
        diff[1] = bLinesDisplay[bIndex];
        aIndex += 1;
        bIndex += 1;
    }
  }

  return printDiffLines(diffs, normalizeDiffOptions(options));
};

// Compare two arrays of strings line-by-line.
export const diffLinesRaw = (