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// Copyright (C) 2018 Leo Balter. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.
/*---
esid: sec-array.prototype.flatMap
description: >
Assert behavior if this value has a custom species constructor
info: |
Array.prototype.flatMap ( mapperFunction [ , thisArg ] )
1. Let O be ? ToObject(this value).
2. Let sourceLen be ? ToLength(? Get(O, "length")).
...
5. Let A be ? ArraySpeciesCreate(O, 0).
6. Perform ? FlattenIntoArray(A, O, sourceLen, 0, 1, mapperFunction, T).
7. Return A.
ArraySpeciesCreate ( originalArray, length )
3. Let isArray be ? IsArray(originalArray).
4. If isArray is false, return ? ArrayCreate(length).
5. Let C be ? Get(originalArray, "constructor").
6. If IsConstructor(C) is true, then
...
7. If Type(C) is Object, then
a. Set C to ? Get(C, @@species).
b. If C is null, set C to undefined.
8. If C is undefined, return ? ArrayCreate(length).
9. If IsConstructor(C) is false, throw a TypeError exception.
10. Return ? Construct(C, « length »).
FlattenIntoArray(target, source, sourceLen, start, depth [ , mapperFunction, thisArg ])
3. Repeat, while sourceIndex < sourceLen
a. Let P be ! ToString(sourceIndex).
b. Let exists be ? HasProperty(source, P).
c. If exists is true, then
...
vi. Else,
...
2. Perform ? CreateDataPropertyOrThrow(target, ! ToString(targetIndex), element).
features: [Array.prototype.flatMap, Symbol, Symbol.species]
includes: [propertyHelper.js]
---*/
assert.sameValue(typeof Array.prototype.flatMap, 'function');
var arr = [[42, 1], [42, 2]];
var mapperFn = function(e) { return e; };
var called = 0;
var ctorCalled = 0;
function ctor(len) {
assert.sameValue(new.target, ctor, 'new target is defined');
assert.sameValue(len, 0, 'first argument is always 0');
ctorCalled++;
}
arr.constructor = {
get [Symbol.species]() {
called++;
return ctor;
}
};
var actual = arr.flatMap(mapperFn);
assert(actual instanceof ctor, 'returned value is an instance of custom ctor');
assert.sameValue(called, 1, 'got species once');
assert.sameValue(ctorCalled, 1, 'called custom ctor once');
assert.sameValue(Object.prototype.hasOwnProperty.call(actual, 'length'), false, 'it does not define an own length property');
verifyProperty(actual, '0', {
configurable: true,
writable: true,
enumerable: true,
value: 42
});
verifyProperty(actual, '1', {
configurable: true,
writable: true,
enumerable: true,
value: 1
});
verifyProperty(actual, '2', {
configurable: true,
writable: true,
enumerable: true,
value: 42
});
verifyProperty(actual, '3', {
configurable: true,
writable: true,
enumerable: true,
value: 2
});
reportCompare(0, 0);
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