57 lines
1.8 KiB
JavaScript
57 lines
1.8 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 AdvanceStringIndex = require('./AdvanceStringIndex');
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var CreateAsyncFromSyncIterator = require('./CreateAsyncFromSyncIterator');
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var GetIteratorFromMethod = require('./GetIteratorFromMethod');
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var GetMethod = require('./GetMethod');
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var IsArray = require('./IsArray');
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var getIteratorMethod = require('../helpers/getIteratorMethod');
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// https://262.ecma-international.org/14.0/#sec-getiterator
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module.exports = function GetIterator(obj, kind) {
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if (kind !== 'sync' && kind !== 'async') {
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throw new $TypeError("Assertion failed: `kind` must be one of 'sync' or 'async', got " + inspect(kind));
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}
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var method;
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if (kind === 'async') { // step 1
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if (hasSymbols && $asyncIterator) {
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method = GetMethod(obj, $asyncIterator); // step 1.a
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}
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}
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if (typeof method === 'undefined') { // step 1.b
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// var syncMethod = GetMethod(obj, $iterator); // step 1.b.i
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var syncMethod = 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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if (kind === 'async') {
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if (typeof syncMethod === 'undefined') {
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throw new $TypeError('iterator method is `undefined`'); // step 1.b.ii
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}
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var syncIteratorRecord = GetIteratorFromMethod(obj, syncMethod); // step 1.b.iii
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return CreateAsyncFromSyncIterator(syncIteratorRecord); // step 1.b.iv
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}
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method = syncMethod; // step 2, kind of
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}
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if (typeof method === 'undefined') {
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throw new $TypeError('iterator method is `undefined`'); // step 3
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}
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return GetIteratorFromMethod(obj, method); // step 4
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};
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