50 lines
1.6 KiB
JavaScript
50 lines
1.6 KiB
JavaScript
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'use strict';
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var $TypeError = require('es-errors/type');
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var Call = require('./Call');
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var CompletionRecord = require('./CompletionRecord');
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var GetMethod = require('./GetMethod');
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var IsCallable = require('./IsCallable');
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var Type = require('./Type');
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// https://262.ecma-international.org/6.0/#sec-iteratorclose
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module.exports = function IteratorClose(iterator, completion) {
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if (Type(iterator) !== 'Object') {
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throw new $TypeError('Assertion failed: Type(iterator) is not Object');
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}
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if (!IsCallable(completion) && !(completion instanceof CompletionRecord)) {
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throw new $TypeError('Assertion failed: completion is not a thunk representing a Completion Record, nor a Completion Record instance');
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}
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var completionThunk = completion instanceof CompletionRecord ? function () { return completion['?'](); } : completion;
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var iteratorReturn = GetMethod(iterator, 'return');
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if (typeof iteratorReturn === 'undefined') {
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return completionThunk();
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}
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var completionRecord;
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try {
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var innerResult = Call(iteratorReturn, iterator, []);
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} catch (e) {
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// if we hit here, then "e" is the innerResult completion that needs re-throwing
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// if the completion is of type "throw", this will throw.
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completionThunk();
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completionThunk = null; // ensure it's not called twice.
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// if not, then return the innerResult completion
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throw e;
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}
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completionRecord = completionThunk(); // if innerResult worked, then throw if the completion does
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completionThunk = null; // ensure it's not called twice.
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if (Type(innerResult) !== 'Object') {
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throw new $TypeError('iterator .return must return an object');
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}
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return completionRecord;
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};
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