Function backtrack

lib/internal/assert/myers_diff.js:80–125

(trace, actual, expected, checkCommaDisparity)

}

function backtrack(trace, actual, expected, checkCommaDisparity) {
  const actualLength = actual.length;
  const expectedLength = expected.length;
  const max = actualLength + expectedLength;

  let x = actualLength;
  let y = expectedLength;
  const result = [];

  for (let diffLevel = trace.length - 1; diffLevel >= 0; diffLevel--) {
    const v = trace[diffLevel];
    const diagonalIndex = x - y;
    const offset = diagonalIndex + max;

    let prevDiagonalIndex;
    if (
      diagonalIndex === -diffLevel ||
      (diagonalIndex !== diffLevel && v[offset - 1] < v[offset + 1])
    ) {
      prevDiagonalIndex = diagonalIndex + 1;
    } else {
      prevDiagonalIndex = diagonalIndex - 1;
    }

    const prevX = v[prevDiagonalIndex + max];
    const prevY = prevX - prevDiagonalIndex;

    while (x > prevX && y > prevY) {
      const actualItem = actual[x - 1];
      const value = checkCommaDisparity && !StringPrototypeEndsWith(actualItem, ',') ? expected[y - 1] : actualItem;
      ArrayPrototypePush(result, [ kOperations.NOP, value ]);
      x--;
      y--;
    }

    if (diffLevel > 0) {
      if (x > prevX) {
        ArrayPrototypePush(result, [ kOperations.INSERT, actual[--x] ]);
      } else {
        ArrayPrototypePush(result, [ kOperations.DELETE, expected[--y] ]);
      }
    }
  }

  return result;
}

function printSimpleMyersDiff(diff) {
  let message = '';