Nodejs Array Exist existsByKey(key, val)

Method Source Code

/*//from w w  w .  ja  v a2s  .  co  m
 * Utility Extension to look into an array
 * of objects by key to determine if it exists already
 */

Array.prototype.existsByKey = function(key, val) {
   var exists = this.map(function(obj) { return obj[key] }).indexOf(val) != -1;
   console.log('Does \'' + val + '\' exist? ' + exists);
   return exists;
}

Related

1. exists(func)

   Array.prototype.exists = function(func) {
     for (var i = 0; i < this.length; i++)
       if (func(this[i]))
         return true;
     return false;
   };
   

2. exists(param, value)

   const DEGREE_TO_RAD = Math.PI / 180
   function max(a, b) {
     return a > b ? a : b;
   function rand(min, max) {
     if (min > max) return rand(max, min);
     if (min == max) return min;
     return min + parseInt(Math.random() * (max - min + 1));
   Math.getUniqueNumber = function() {
     function s4() {
       return Math.floor((1 + Math.random()) * 0x10000)
         .toString(16)
         .substring(1);
     return s4() + s4() + '-' + s4() + '-' + s4() + '-' +
       s4() + '-' + s4() + s4() + s4();
   Array.prototype.exists = function(param, value) {
     var found = -1;
     this.forEach(function(e, i) {
       if (typeof e[param] != 'undefined') {
         if (e[param] == value) {
           found = i;
     })
     return found;