JSTests/test262/test/built-ins/TypedArray/prototype/map/speciesctor-get-species-custom-ctor-returns-another-instance.js

// Copyright (C) 2018 Peter Wong. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.
/*---
esid: sec-%typedarray%.prototype.map
description: >
  Custom @@species constructor may return a different TypedArray
info: |
  22.2.3.19 %TypedArray%.prototype.map ( callbackfn [ , thisArg ] )

  ...
  6. Let A be ? TypedArraySpeciesCreate(O, « len »).
  ...

  22.2.4.7 TypedArraySpeciesCreate ( exemplar, argumentList )

  ...
  3. Let constructor be ? SpeciesConstructor(exemplar, defaultConstructor).
  4. Return ? TypedArrayCreate(constructor, argumentList).

  7.3.20 SpeciesConstructor ( O, defaultConstructor )

  ...
  5. Let S be ? Get(C, @@species).
  ...
  7. If IsConstructor(S) is true, return S.
  ...

  22.2.4.6 TypedArrayCreate ( constructor, argumentList )

  1. Let newTypedArray be ? Construct(constructor, argumentList).
  2. Perform ? ValidateTypedArray(newTypedArray).
  3. If argumentList is a List of a single Number, then
    ...
  4. Return newTypedArray.
includes: [testTypedArray.js, compareArray.js]
features: [Symbol.species, TypedArray]
---*/

testWithTypedArrayConstructors(function(TA) {
  var sample = new TA([40]);
  var otherTA = TA === Int8Array ? Int16Array : Int8Array;
  var other = new otherTA([1, 0, 1]);
  var result;

  sample.constructor = {};
  sample.constructor[Symbol.species] = function() {
    return other;
  };

  result = sample.map(function(a) { return a + 7; });

  assert.sameValue(result, other, "returned another typedarray");
  assert(compareArray(result, [47, 0, 1]), "values are set on returned typedarray");
});