Nodejs Array Find find(filter)

Here you can find the source of find(filter)

Method Source Code

Array.prototype.find = function(filter) {
  if(typeof filter != 'function') {
    throw new Error('First argument must be a function');
  }/*from  w w  w . j  a  va 2  s. c  o  m*/
  for(var i=0; i<this.length; i++) {
    var element = this[i];
    if(filter(element, i)) {
      return element;
    }
  }
};

Related

  1. find(criteria)
    Array.prototype.find = function(criteria) {
      for (var i = 0; i < this.length; i++) {
        if (criteria(this[i])) {
          return this[i]
      return null
    Math.sign = function(x) {
    ...
    
  2. find(element)
    Array.prototype.find = function (element) {
      if (typeof element === 'function') {
        return element(this);
      var len = this.length;
      for (var i = 0; i < len; i++) {
        if(this[i] === element) {
          return element;
      return -1;
    var doPow = function (array) {
      var len = array.length;
      for(var i = 0; i < len; i++) {
        array[i] *= array[i]; 
      return array;
    var b = [1, 2, 3, 4, 5, 6];
    console.log(b.find(doPow));
    
  3. find(element)
    Array.prototype.find = function(element) {
        var i;
        for (i = 0; i < this.length; i += 1) {
            if (this[i] === element) {
                return i;
        return false;
    
  4. find(element)
    Array.prototype.find=function(element){
        var i;
        for(i=0;i<this.length;i+=1){
            if(this[i]===element){
                return i;
        return false;
    Array.prototype.remove=function(element){
        var i;
        for(i=0;i<this.length;i+=1){
            if(this[i]===element){
                this.splice(i,1)
                return true;
        return false;
    var arr=['a','b','c','d','e','f','g','h'];
    arr.remove('e');
    arr.remove('f');
    var i;
    for(i=0;i<arr.length;i+=1){
        console.log(arr[i]);
    
  5. find(f)
    Array.prototype.find = function(f) {
      for (var i = 0; i < this.length; i++) {
        if (f(this[i]))
          return this[i];
    };
    
  6. find(fn)
    Array.prototype.find = function(fn) {
        for (var i = 0; i < this.length; i++) {
            if (fn(this[i])) {
                return this[i];
    
  7. find(fn, v)
    Array.prototype.find = function(fn, v) {
        var isFN = typeof(fn) === 'function';
        var isV = v !== undefined;
        for (var i = 0, len = this.length; i < len; i++) {
            if (isFN) {
                if (fn(this[i], i)) {
                    return this[i];
                continue;
    ...
    
  8. find(id)
    Array.prototype.find = function(id) {
      return this.filter(function(a) {
        if ( a.id == id ) {
          return a;
      }).first();
    
  9. find(isOk)
    const array = [1, 42, 7, 9, 13, 10, 20, 35, 45, -7, -3, 0, 4, -1, 15];
    Array.prototype.find = function(isOk) {
      const len = this.length;
      for(let i = 0; i < len; i += 1) {
        if(isOk(this[i], i, this)) {
          return this[i];
    Array.prototype.findIndex = function(isOk) {
      const len = this.length;
      for(let i = 0; i < len; i += 1) {
        if(isOk(this[i], i, this)) {
          return i;
      return -1;
    console.log(array.find(x => x % 2 === 0));
    console.log(array.find(x => x % 2 === 1));
    console.log(array.find(x => x > 10 && x < 20));
    console.log(array.find(x => x === 45));
    console.log(array.find(x => x === 46));
    console.log(array.findIndex(x => x % 2 === 0));
    console.log(array.findIndex(x => x % 2 === 1));
    console.log(array.findIndex(x => x > 10 && x < 20));
    console.log(array.findIndex(x => x === 45));
    console.log(array.findIndex(x => x === 46));