Constnium/node_modules/es-abstract/2021/GetIterator.js
2022-06-23 02:27:43 +02:00

64 lines
1.7 KiB
JavaScript

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