core-js/modules/es.array.iterator.js

'use strict';
var toIndexedObject = require('../internals/to-indexed-object');
var addToUnscopables = require('../internals/add-to-unscopables');
var Iterators = require('../internals/iterators');
var InternalStateModule = require('../internals/internal-state');
var defineProperty = require('../internals/object-define-property').f;
var defineIterator = require('../internals/iterator-define');
var createIterResultObject = require('../internals/create-iter-result-object');
var IS_PURE = require('../internals/is-pure');
var DESCRIPTORS = require('../internals/descriptors');

var ARRAY_ITERATOR = 'Array Iterator';
var setInternalState = InternalStateModule.set;
var getInternalState = InternalStateModule.getterFor(ARRAY_ITERATOR);

// `Array.prototype.entries` method
// https://tc39.es/ecma262/#sec-array.prototype.entries
// `Array.prototype.keys` method
// https://tc39.es/ecma262/#sec-array.prototype.keys
// `Array.prototype.values` method
// https://tc39.es/ecma262/#sec-array.prototype.values
// `Array.prototype[@@iterator]` method
// https://tc39.es/ecma262/#sec-array.prototype-@@iterator
// `CreateArrayIterator` internal method
// https://tc39.es/ecma262/#sec-createarrayiterator
module.exports = defineIterator(Array, 'Array', function (iterated, kind) {
  setInternalState(this, {
    type: ARRAY_ITERATOR,
    target: toIndexedObject(iterated), // target
    index: 0,                          // next index
    kind: kind                         // kind
  });
// `%ArrayIteratorPrototype%.next` method
// https://tc39.es/ecma262/#sec-%arrayiteratorprototype%.next
}, function () {
  var state = getInternalState(this);
  var target = state.target;
  var index = state.index++;
  if (!target || index >= target.length) {
    state.target = undefined;
    return createIterResultObject(undefined, true);
  }
  switch (state.kind) {
    case 'keys': return createIterResultObject(index, false);
    case 'values': return createIterResultObject(target[index], false);
  } return createIterResultObject([index, target[index]], false);
}, 'values');

// argumentsList[@@iterator] is %ArrayProto_values%
// https://tc39.es/ecma262/#sec-createunmappedargumentsobject
// https://tc39.es/ecma262/#sec-createmappedargumentsobject
var values = Iterators.Arguments = Iterators.Array;

// https://tc39.es/ecma262/#sec-array.prototype-@@unscopables
addToUnscopables('keys');
addToUnscopables('values');
addToUnscopables('entries');

// V8 ~ Chrome 45- bug
if (!IS_PURE && DESCRIPTORS && values.name !== 'values') try {
  defineProperty(values, 'name', { value: 'values' });
} catch (error) { /* empty */ }