65 lines
1.7 KiB
JavaScript
65 lines
1.7 KiB
JavaScript
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'use strict';
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var GetIntrinsic = require('get-intrinsic');
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var $TypeError = GetIntrinsic('%TypeError%');
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var $asyncIterator = GetIntrinsic('%Symbol.asyncIterator%', true);
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var inspect = require('object-inspect');
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var hasSymbols = require('has-symbols')();
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var getIteratorMethod = require('../helpers/getIteratorMethod');
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var AdvanceStringIndex = require('./AdvanceStringIndex');
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var Call = require('./Call');
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var GetMethod = require('./GetMethod');
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var IsArray = require('./IsArray');
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var Type = require('./Type');
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// https://262.ecma-international.org/9.0/#sec-getiterator
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module.exports = function GetIterator(obj, hint, method) {
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var actualHint = hint;
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if (arguments.length < 2) {
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actualHint = 'sync';
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}
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if (actualHint !== 'sync' && actualHint !== 'async') {
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throw new $TypeError("Assertion failed: `hint` must be one of 'sync' or 'async', got " + inspect(hint));
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}
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var actualMethod = method;
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if (arguments.length < 3) {
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if (actualHint === 'async') {
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if (hasSymbols && $asyncIterator) {
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actualMethod = GetMethod(obj, $asyncIterator);
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}
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if (actualMethod === undefined) {
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throw new $TypeError("async from sync iterators aren't currently supported");
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}
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} else {
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actualMethod = getIteratorMethod(
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{
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AdvanceStringIndex: AdvanceStringIndex,
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GetMethod: GetMethod,
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IsArray: IsArray
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},
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obj
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);
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}
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}
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var iterator = Call(actualMethod, obj);
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if (Type(iterator) !== 'Object') {
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throw new $TypeError('iterator must return an object');
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}
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return iterator;
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// TODO: This should return an IteratorRecord
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/*
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var nextMethod = GetV(iterator, 'next');
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return {
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'[[Iterator]]': iterator,
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'[[NextMethod]]': nextMethod,
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'[[Done]]': false
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};
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*/
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};
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