JSTests/test262/harness/compareArray.js

// Copyright (C) 2017 Ecma International.  All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.
/*---
description: |
    Compare the contents of two arrays
defines: [compareArray]
---*/

function compareArray(a, b) {
  if (b.length !== a.length) {
    return false;
  }

  for (var i = 0; i < a.length; i++) {
    if (!compareArray.isSameValue(b[i], a[i])) {
      return false;
    }
  }
  return true;
}

compareArray.isSameValue = function(a, b) {
  if (a === 0 && b === 0) return 1 / a === 1 / b;
  if (a !== a && b !== b) return true;

  return a === b;
};

compareArray.format = function(arrayLike) {
  return `[${[].map.call(arrayLike, String).join(', ')}]`;
};

assert.compareArray = function(actual, expected, message) {
  message  = message === undefined ? '' : message;

  if (typeof message === 'symbol') {
    message = message.toString();
  }

  assert(actual != null, `First argument shouldn't be nullish. ${message}`);
  assert(expected != null, `Second argument shouldn't be nullish. ${message}`);
  var format = compareArray.format;
  var result = compareArray(actual, expected);

  // The following prevents actual and expected from being iterated and evaluated
  // more than once unless absolutely necessary.
  if (!result) {
    assert(false, `Expected ${format(actual)} and ${format(expected)} to have the same contents. ${message}`);
  }
};