odin-js-fundamentals-part-4/node_modules/es-abstract/2018/IsConcatSpreadable.js

26 lines
621 B
JavaScript

'use strict';
var GetIntrinsic = require('get-intrinsic');
var $isConcatSpreadable = GetIntrinsic('%Symbol.isConcatSpreadable%', true);
var Get = require('./Get');
var IsArray = require('./IsArray');
var ToBoolean = require('./ToBoolean');
var Type = require('./Type');
// https://262.ecma-international.org/6.0/#sec-isconcatspreadable
module.exports = function IsConcatSpreadable(O) {
if (Type(O) !== 'Object') {
return false;
}
if ($isConcatSpreadable) {
var spreadable = Get(O, $isConcatSpreadable);
if (typeof spreadable !== 'undefined') {
return ToBoolean(spreadable);
}
}
return IsArray(O);
};