odin-js-fundamentals-part-4/node_modules/es-abstract/2023/IteratorClose.js

63 lines
2.1 KiB
JavaScript

'use strict';
var GetIntrinsic = require('get-intrinsic');
var $TypeError = GetIntrinsic('%TypeError%');
var Call = require('./Call');
var CompletionRecord = require('./CompletionRecord');
var GetMethod = require('./GetMethod');
var IsCallable = require('./IsCallable');
var Type = require('./Type');
var assertRecord = require('../helpers/assertRecord');
// https://262.ecma-international.org/14.0/#sec-iteratorclose
module.exports = function IteratorClose(iteratorRecord, completion) {
assertRecord(Type, 'Iterator Record', 'iteratorRecord', iteratorRecord);
if (Type(iteratorRecord['[[Iterator]]']) !== 'Object') {
throw new $TypeError('Assertion failed: iteratorRecord.[[Iterator]] must be an Object'); // step 1
}
if (!IsCallable(completion) && !(completion instanceof CompletionRecord)) { // step 2
throw new $TypeError('Assertion failed: completion is not a thunk representing a Completion Record, nor a Completion Record instance');
}
var completionThunk = completion instanceof CompletionRecord ? function () { return completion['?'](); } : completion;
var iterator = iteratorRecord['[[Iterator]]']; // step 3
var iteratorReturn;
try {
iteratorReturn = GetMethod(iterator, 'return'); // step 4
} catch (e) {
completionThunk(); // throws if `completion` is a throw completion // step 6
completionThunk = null; // ensure it's not called twice.
throw e; // step 7
}
if (typeof iteratorReturn === 'undefined') {
return completionThunk(); // step 5.a - 5.b
}
var innerResult;
try {
innerResult = Call(iteratorReturn, iterator, []);
} catch (e) {
// if we hit here, then "e" is the innerResult completion that needs re-throwing
completionThunk(); // throws if `completion` is a throw completion // step 6
completionThunk = null; // ensure it's not called twice.
// if not, then return the innerResult completion
throw e; // step 7
}
var completionRecord = completionThunk(); // if innerResult worked, then throw if the completion does
completionThunk = null; // ensure it's not called twice.
if (Type(innerResult) !== 'Object') {
throw new $TypeError('iterator .return must return an object');
}
return completionRecord;
};