findLast_findLastIndex.js

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/* -*- indent-tabs-mode: nil; js-indent-level: 2 -*- */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

//-----------------------------------------------------------------------------

var BUGNUMBER = 1704385;

var summary = 'Array.prototype.findLast and Array.prototype.findLastIndex';

print(BUGNUMBER + ": " + summary);

/**************

 * BEGIN TEST *

 **************/

function isString(v, index, array)

  assertEq(array[index], v);

  return typeof v == 'string';

function dumpError(e)

  var s = e.name + ': ' + e.message +

    ' File: ' + e.fileName +

    ', Line: ' + e.lineNumber +

    ', Stack: ' + e.stack;

  return s;

var expect;

var actual;

var obj;

var strings = ['hello', 'Array', 'WORLD'];

var mixed   = [0, '1', 2];

var sparsestrings = new Array();

sparsestrings[2] = 'sparse';

var arraylike = {0:0, 1:'string', 2:2, length:3};

// array for which JSObject::isIndexed() holds.

var indexedArray = [];

Object.defineProperty(indexedArray, 42, { get: function() { return 42; } });

Object.defineProperty(indexedArray, 142, { get: function() { return 'string'; } });

// findLast and findLastIndex have 1 required argument

expect = 1;

actual = Array.prototype.findLast.length;

reportCompare(expect, actual, 'Array.prototype.findLast.length == 1');

actual = Array.prototype.findLastIndex.length;

reportCompare(expect, actual, 'Array.prototype.findLastIndex.length == 1');

// throw TypeError if no predicate specified

expect = 'TypeError';

try

  strings.findLast();

  actual = 'no error';

catch(e)

  actual = e.name;

reportCompare(expect, actual, 'Array.findLast(undefined) throws TypeError');

try

  strings.findLastIndex();

  actual = 'no error';

catch(e)

  actual = e.name;

reportCompare(expect, actual, 'Array.findLastIndex(undefined) throws TypeError');

// Length gets treated as integer, not uint32

obj = { length: -4294967295, 0: 42 };

expected = undefined;

actual = Array.prototype.findLast.call(obj, () => true);

reportCompare(expected, actual, 'findLast correctly treats "length" as an integer');

expected = -1

actual = Array.prototype.findLastIndex.call(obj, () => true);

reportCompare(expected, actual, 'findLastIndex correctly treats "length" as an integer');

// test findLast and findLastIndex results

try

  expect = 'WORLD';

  actual = strings.findLast(isString);

catch(e)

  actual = dumpError(e);

reportCompare(expect, actual, 'strings: findLast finds last string element');

try

  expect = 2;

  actual = strings.findLastIndex(isString);

catch(e)

  actual = dumpError(e);

reportCompare(expect, actual, 'strings: findLastIndex finds last string element');

try

  expect = '1';

  actual = mixed.findLast(isString);

catch(e)

  actual = dumpError(e);

reportCompare(expect, actual, 'mixed: findLast finds last string element');

try

  expect = 1;

  actual = mixed.findLastIndex(isString);

catch(e)

  actual = dumpError(e);

reportCompare(expect, actual, 'mixed: findLastIndex finds last string element');

try

  expect = 'sparse';

  actual = sparsestrings.findLast(isString);

catch(e)

  actual = dumpError(e);

reportCompare(expect, actual, 'sparsestrings: findLast finds last string element');

try

  expect = 2;

  actual = sparsestrings.findLastIndex(isString);

catch(e)

  actual = dumpError(e);

reportCompare(expect, actual, 'sparsestrings: findLastIndex finds first string element');

try

  expect = 'string';

  actual = [].findLast.call(arraylike, isString);

catch(e)

  actual = dumpError(e);

reportCompare(expect, actual, 'arraylike: findLast finds last string element');

try

  expect = 1;

  actual = [].findLastIndex.call(arraylike, isString);

catch(e)

  actual = dumpError(e);

reportCompare(expect, actual, 'arraylike: findLastIndex finds last string element');

try

  expect = 1;

  actual = 0;

  Array.prototype.findLast.call({get 0(){ actual++ }, length: 1}, ()=>true);

catch(e)

  actual = dumpError(e);

reportCompare(expect, actual, 'arraylike with getter: getter only called once');

try

  expect = 'string';

  actual = [].findLast.call(indexedArray, isString);

catch(e)

  actual = dumpError(e);

reportCompare(expect, actual, 'indexedArray: findLast finds last string element');

try

  expect = 142;

  actual = [].findLastIndex.call(indexedArray, isString);

catch(e)

  actual = dumpError(e);

reportCompare(expect, actual, 'indexedArray: findLastIndex finds last string element');

// Bug 1058394 - Array#findLast and Array#findLastIndex no longer skip holes too.

var sparseArray = [1,,];

var sparseArrayWithInheritedDataProperty = Object.setPrototypeOf([1,,,], {

  __proto__: [].__proto__,

  2 : 0

});

var sparseArrayWithInheritedAccessorProperty = Object.setPrototypeOf([1,,,], {

  __proto__: [].__proto__,

  get 2(){

    throw "get 2";

});

try

  expect = undefined;

  actual = sparseArray.findLast(() => true);

catch(e)

  actual = dumpError(e);

reportCompare(expect, actual, "Don't skip holes in Array#findLast.");

try

  expect = 1;

  actual = sparseArray.findLastIndex(() => true);

catch(e)

  actual = dumpError(e);

reportCompare(expect, actual, "Don't skip holes in Array#findLastIndex.");

try

  expect = 0;

  actual = sparseArrayWithInheritedDataProperty.findLast(v => v === 0);

catch(e)

  actual = dumpError(e);

reportCompare(expect, actual, "Array#findLast can find inherited data property.");

try

  expect = 2;

  actual = sparseArrayWithInheritedDataProperty.findLastIndex(v => v === 0);

catch(e)

  actual = dumpError(e);

reportCompare(expect, actual, "Array#findLastIndex can find inherited data property.");

try

  expect = "get 2";

  actual = sparseArrayWithInheritedAccessorProperty.findLast(() => true);

catch(e)

  actual = e;

reportCompare(expect, actual, "Array#findLast can find inherited accessor property.");

try

  expect = "get 2";

  actual = sparseArrayWithInheritedAccessorProperty.findLastIndex(() => true);

catch(e)

  actual = e;

reportCompare(expect, actual, "Array#findLastIndex can find inherited accessor property.");