Nodejs Array Index indexOf(searchElement)

Method Source Code

/**//from  w w w  . j  ava  2  s  .  co  m
 * Array.prototype.indexOf Polyfill
 */

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

/* End of file indexof.js */

Related

1. 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;
   

2. 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;
   };
   

3. indexOf(s)

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

4. 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])  
   ...
   

5. indexOf(searchElement /*, fromIndex */)

   if (!Array.prototype.indexOf) {
     Array.prototype.indexOf = function (searchElement ) {
       'use strict';
       if (this == null) {
         throw new TypeError();
       var n, k, t = Object(this),
         len = t.length >>> 0;
       if (len === 0) {
   ...
   

6. 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;
   

7. 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){
   ...
   

8. 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) {
   ...
   

9. indexOf(substr,start)

   Array.prototype.indexOf=function(substr,start)
     var ta,rt,d='\0';
     if(start!=null){ta=this.slice(start);rt=start;}else{ta=this;rt=0;}
     var str=d+ta.join(d)+d,t=str.indexOf(d+substr+d);
     if(t==-1)return -1;rt+=str.slice(0,t).replace(/[^\0]/g,'').length;
     return rt;