debian-mirror-gitlab/core-js/internals/define-iterator.js
2019-09-25 13:30:05 +05:30

90 lines
3.9 KiB
JavaScript

'use strict';
var $ = require('../internals/export');
var createIteratorConstructor = require('../internals/create-iterator-constructor');
var getPrototypeOf = require('../internals/object-get-prototype-of');
var setPrototypeOf = require('../internals/object-set-prototype-of');
var setToStringTag = require('../internals/set-to-string-tag');
var hide = require('../internals/hide');
var redefine = require('../internals/redefine');
var wellKnownSymbol = require('../internals/well-known-symbol');
var IS_PURE = require('../internals/is-pure');
var Iterators = require('../internals/iterators');
var IteratorsCore = require('../internals/iterators-core');
var IteratorPrototype = IteratorsCore.IteratorPrototype;
var BUGGY_SAFARI_ITERATORS = IteratorsCore.BUGGY_SAFARI_ITERATORS;
var ITERATOR = wellKnownSymbol('iterator');
var KEYS = 'keys';
var VALUES = 'values';
var ENTRIES = 'entries';
var returnThis = function () { return this; };
module.exports = function (Iterable, NAME, IteratorConstructor, next, DEFAULT, IS_SET, FORCED) {
createIteratorConstructor(IteratorConstructor, NAME, next);
var getIterationMethod = function (KIND) {
if (KIND === DEFAULT && defaultIterator) return defaultIterator;
if (!BUGGY_SAFARI_ITERATORS && KIND in IterablePrototype) return IterablePrototype[KIND];
switch (KIND) {
case KEYS: return function keys() { return new IteratorConstructor(this, KIND); };
case VALUES: return function values() { return new IteratorConstructor(this, KIND); };
case ENTRIES: return function entries() { return new IteratorConstructor(this, KIND); };
} return function () { return new IteratorConstructor(this); };
};
var TO_STRING_TAG = NAME + ' Iterator';
var INCORRECT_VALUES_NAME = false;
var IterablePrototype = Iterable.prototype;
var nativeIterator = IterablePrototype[ITERATOR]
|| IterablePrototype['@@iterator']
|| DEFAULT && IterablePrototype[DEFAULT];
var defaultIterator = !BUGGY_SAFARI_ITERATORS && nativeIterator || getIterationMethod(DEFAULT);
var anyNativeIterator = NAME == 'Array' ? IterablePrototype.entries || nativeIterator : nativeIterator;
var CurrentIteratorPrototype, methods, KEY;
// fix native
if (anyNativeIterator) {
CurrentIteratorPrototype = getPrototypeOf(anyNativeIterator.call(new Iterable()));
if (IteratorPrototype !== Object.prototype && CurrentIteratorPrototype.next) {
if (!IS_PURE && getPrototypeOf(CurrentIteratorPrototype) !== IteratorPrototype) {
if (setPrototypeOf) {
setPrototypeOf(CurrentIteratorPrototype, IteratorPrototype);
} else if (typeof CurrentIteratorPrototype[ITERATOR] != 'function') {
hide(CurrentIteratorPrototype, ITERATOR, returnThis);
}
}
// Set @@toStringTag to native iterators
setToStringTag(CurrentIteratorPrototype, TO_STRING_TAG, true, true);
if (IS_PURE) Iterators[TO_STRING_TAG] = returnThis;
}
}
// fix Array#{values, @@iterator}.name in V8 / FF
if (DEFAULT == VALUES && nativeIterator && nativeIterator.name !== VALUES) {
INCORRECT_VALUES_NAME = true;
defaultIterator = function values() { return nativeIterator.call(this); };
}
// define iterator
if ((!IS_PURE || FORCED) && IterablePrototype[ITERATOR] !== defaultIterator) {
hide(IterablePrototype, ITERATOR, defaultIterator);
}
Iterators[NAME] = defaultIterator;
// export additional methods
if (DEFAULT) {
methods = {
values: getIterationMethod(VALUES),
keys: IS_SET ? defaultIterator : getIterationMethod(KEYS),
entries: getIterationMethod(ENTRIES)
};
if (FORCED) for (KEY in methods) {
if (BUGGY_SAFARI_ITERATORS || INCORRECT_VALUES_NAME || !(KEY in IterablePrototype)) {
redefine(IterablePrototype, KEY, methods[KEY]);
}
} else $({ target: NAME, proto: true, forced: BUGGY_SAFARI_ITERATORS || INCORRECT_VALUES_NAME }, methods);
}
return methods;
};