source: imaps-frontend/node_modules/es-abstract/2016/IteratorClose.js@ 79a0317

'use strict';

var $TypeError = require('es-errors/type');

var Call = require('./Call');
var CompletionRecord = require('./CompletionRecord');
var GetMethod = require('./GetMethod');
var IsCallable = require('./IsCallable');

var isObject = require('../helpers/isObject');

// https://262.ecma-international.org/6.0/#sec-iteratorclose

module.exports = function IteratorClose(iterator, completion) {
        if (!isObject(iterator)) {
                throw new $TypeError('Assertion failed: Type(iterator) is not Object');
        }
        if (!IsCallable(completion) && !(completion instanceof CompletionRecord)) {
                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 iteratorReturn = GetMethod(iterator, 'return');

        if (typeof iteratorReturn === 'undefined') {
                return completionThunk();
        }

        var completionRecord;
        try {
                var innerResult = Call(iteratorReturn, iterator, []);
        } catch (e) {
                // if we hit here, then "e" is the innerResult completion that needs re-throwing

                // if the completion is of type "throw", this will throw.
                completionThunk();
                completionThunk = null; // ensure it's not called twice.

                // if not, then return the innerResult completion
                throw e;
        }
        completionRecord = completionThunk(); // if innerResult worked, then throw if the completion does
        completionThunk = null; // ensure it's not called twice.

        if (!isObject(innerResult)) {
                throw new $TypeError('iterator .return must return an object');
        }

        return completionRecord;
};