Nodejs Array Filter filter(fun /*, thisp*/)

Method Source Code

/**//w  ww .  ja  v  a 2s.c om
 * Applies `fun` to each element of the array and returns a new array of all
 * the values for which `fun` returned `true`.
 *
 * The first argument given to `fun` is a single array element and the second
 * argument is the index of that element in the array.
 *
 * This definition is compatible with the JavaScript 1.6 definition for
 * `Array#filter` in Spidermonkey and with the definition in the Prototype library.
 *
 * This implementation comes from:
 * https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Global_Objects/Array/filter
 *
 * @function
 * @param   {Function}  fun     predicate function that will be applied to each
 * array element
 * @param   {Object}    [thisp] context in which `fun` will be invoked - `this`
 * in `fun` will refer to `thisp`
 * @returns {Array} a new array containing only the elements for which `fun` return true
 */
Array.prototype.filter = Array.prototype.filter || function(fun /*, thisp*/) {
    var len = this.length >>> 0;
    if (typeof fun != "function") {
        throw new TypeError();
    }

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

    return res;
};

Related

1. filter(fn)

   Array.prototype.filter = function(fn){
       var self = this;
       var arr = [];
       for(var i=0; i<self.length; i++){
           if (fn(self[i])){
               arr.push(self[i]);
       return arr;
   ...
   

2. filter(fn)

   Array.prototype.filter = function(fn)
       r = [];
       this.forEach(function (item) { if (fn(item)) r.push(item); });
       return r;
   

3. filter(fn, context)

   Array.prototype.filter = function(fn, context) {
     if (typeof fn != "function") {
       throw new TypeError(fn + " is not a function");
     if (typeof context === 'undefined') {
       context = this;
     var res = [];
     for (var i = 0, l = this.length; i < l; ++i) {
   ...
   

4. filter(fun /*, thisArg */)

   "use strict";
   Array.isArray = function(arg) {
       return Object.prototype.toString.call(arg) === '[object Array]';
   };
   Array.prototype.filter = function(fun ) {
       if (this === void 0 || this === null)
           throw new TypeError();
       var t = Object(this);
       var len = t.length >>> 0;
   ...
   

5. filter(fun /*, thisp */)

   Array.prototype.filter = Array.prototype.filter || function(fun ) {
     "use strict";
     if (this === void 0 || this === null) throw new TypeError();
     var t = Object(this);
     var len = t.length >>> 0;
     if (typeof fun !== "function") throw new TypeError();
     var res = [];
     var thisp = arguments[1];
     for (var i = 0; i < len; i++) {
   ...
   

6. filter(fun)

   "use strict";
   Array.prototype.filter = function (fun) {
       let filtered = [];
       for (let i = 0; i < this.length; i++) {
           if (fun(this[i])) {
               filtered.push(this[i]);
       return filtered;
   ...
   

7. filter(fun)

   "use strict";
   Array.prototype.filter = function (fun) {
       let arr = [];
       let thisArg = arguments.length >= 2 ? arguments[1] : void 0;
       for (let i = 0; i < this.length; i++) {
           if (fun.call(thisArg, this[i], i, this)) {
               arr.push(this[i]);
       return arr;
   

8. filter(fun)

   Array.prototype.filter = function (fun) {
       var len = this.length;
       var res = [];
       var thisArg = void 0;
       for (var i = 0; i < len; i++) {
           var val = this[i];
           if (fun.call(thisArg, val)) {
               res.push(val);
       return res;
   };
   

9. filter(fun)

   Array.prototype.filter = function(fun) {
     "use strict";
     var i, len, res, t, thisArg, val;
     if (this === void 0 || this === null) {
       throw new TypeError();
     t = Object(this);
     len = t.length >>> 0;
     if (typeof fun !== "function") {
   ...