Nodejs Array Index indexOf(searchElement /*, fromIndex */)

Method Source Code

if (!Array.prototype.indexOf) {
  Array.prototype.indexOf = function (searchElement /*, fromIndex */) {
    'use strict';
    if (this == null) {
      throw new TypeError();/*from   w w  w .  j a  v  a  2s .co m*/
    }
    var n, k, t = Object(this),
      len = t.length >>> 0;

    if (len === 0) {
      return -1;
    }
    n = 0;
    if (arguments.length > 1) {
      n = Number(arguments[1]);
      if (n != n) { // shortcut for verifying if it's NaN
        n = 0;
      } else if (n != 0 && n != Infinity && n != -Infinity) {
        n = (n > 0 || -1) * Math.floor(Math.abs(n));
      }
    }
    if (n >= len) {
      return -1;
    }
    for (k = n >= 0 ? n : Math.max(len - Math.abs(n), 0); k < len; k++) {
      if (k in t && t[k] === searchElement) {
        return k;
      }
    }
    return -1;
  };
}

Related

1. indexOf(obj, start)

   Array.prototype.indexOf = function(obj, start) {
        for (var i = (start || 0), j = this.length; i < j; i++) {
            if (this[i] === obj) { return i; }
        return -1;
   

2. indexOf(obj, start)

   'use strict';
   Array.prototype.indexOf = function(obj, start) {
      for (var i = (start || 0), j = this.length; i < j; i++) {
          if (this[i] === obj) { 
              return i; 
      return -1;
   

3. indexOf(object)

   Array.prototype.indexOf = function(object) {
     for (var i = 0, length = this.length; i < length; i++)
       if (this[i] == object) return i;
     return -1;
   };
   

4. indexOf(s)

   Array.prototype.indexOf = function(s)
     for (var i = 0; i < this.length; ++i )
       if(this[i] == s) return i;
     return -1;
   };
   

5. indexOf(s)

   Array.prototype.indexOf = function(s) {
     if(undefined!=s.position){
       for (var i = 0; i < this.length; i++) {  
             if (s.position == this[i].position)  
                 return i;  
     }else{
       for (var i = 0; i < this.length; i++) {  
             if (s == this[i])  
   ...
   

6. indexOf(searchElement)

   Array.prototype.indexOf = function(searchElement) {
     "use strict";
     if (this === void 0 || this === null) {
       throw new TypeError();
     var t = Object(this);
     var len = t.length >>> 0;
     if (len === 0) {return -1;}
     var n = 0;
   ...
   

7. indexOf(searchElement, fromIndex)

   Array.prototype.indexOf = function(searchElement, fromIndex) {
     if (!fromIndex || !isFinite(fromIndex)) {
       fromIndex = 0;
     for (var i = fromIndex, l = this.length; i < l; ++i) {
       if (this.hasOwnProperty(i) && this[i] === searchElement) {
         return i;
     return -1;
   

8. indexOf(showMe)

   Array.prototype.indexOf = function(showMe){
       for(identification in this){
           if(this[identification] == showMe){return identification}
       return undefined
   Array.prototype.max = function(){
     var max = 0;
     for(num in this){
   ...
   

9. indexOf(src, form)

   'use strict';
   var arr = [
       'a', 'b', 'c', 'd', '1', 1, '0'
   ]
   console.log(arr.indexOf('b'));
   console.log(arr.indexOf(1, 3));
   console.log(arr.indexOf(13, 3));
   console.log(arr.indexOf('d'));
   Array.prototype.indexOf = function(src, form) {
   ...