JSFiddle - React, Tailwind, and code Playground

by heera

JavaScript

if (!Array.prototype.filter) {
        Array.prototype.filter = function(fun /*, thisp*/) {
            var len = this.length >>> 0;
            if (typeof fun != "function") {
                throw new TypeError();
            }

            var res = [];
            var thisp = arguments[1]; 
            for (var i = 0; i < len; i++) {
                if (i in this) {
                    var val = this[i];
                    if (fun.call(thisp, val, i, this)) {
                        res.push(val);
                    }
                }
            }
            return res;
        };
    }

    var sparse = [];
    sparse[1] = undefined;
    sparse[5] = 3;
    sparse[10] = null;

    dense=sparse.filter(function(a){
        return a!== undefined && a != null;;
    });
alert(dense);