JSFiddle - React, Tailwind, and code Playground

by Xeon06

JavaScript

var a = [];
a[1] = "foo";
a.forEach(function(v, i) { console.log(i, v); }); //All good

Array.prototype.forEach=function(callback,thisArg){var T,k;if(this==null){throw new TypeError(" this is null or not defined");}var O=Object(this);var len=O.length>>>0;if({}.toString.call(callback)!="[object Function]"){throw new TypeError(callback+" is not a function");}if(thisArg){T=thisArg;}k=0;while(k<len){var kValue;if(k in O){kValue=O[Pk];callback.call(T,kValue,k,O);}k++;}};

var a = [];
a[1] = "foo";
a.forEach(function(v, i) { console.log(i, v); }); //Reference error