Nodejs Array Index indexOf(elt /*, from*/)

Method Source Code

/**/*from w ww .j  ava  2 s  .c  o  m*/
 * Compares elements in the array with `searchElement` using strict equality
 * (===).  If any element matches `searchElement` the lowest matching index is
 * returned.  Otherwise -1 is returned.
 *
 * You can optionally restrict the search by passing a `fromIndex` argument.
 *
 * This definition is compatible with the JavaScript 1.6 definition for
 * `Array#indexOf` in Spidermonkey.
 *
 * This implementation comes from:
 * https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Global_Objects/Array/indexOf
 *
 * @function
 * @param   {any}       searchElement   element to search for within the array
 * @param   {number}    [fromIndex]     index at which to begin search
 * @returns {number}    the index of the matching element if one is found, -1 otherwise
 */
Array.prototype.indexOf = Array.prototype.indexOf || function(elt /*, from*/) {
    var len = this.length >>> 0;

    var from = Number(arguments[1]) || 0;
    from = (from < 0)
        ? Math.ceil(from)
        : Math.floor(from);
    if (from < 0) {
        from += len;
    }

    for (; from < len; from++) {
        if (from in this &&
            this[from] === elt) {
            return from;
        }
    }
    return -1;
};

Related

1. indexOf(elem)

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

2. indexOf(elem, from)

   Array.prototype.indexOf = function(elem, from) {
     if (from == null) {
       from = 0;
     } else if (from < 0) {
       from = Math.max(0, this.length + from);
     for (var i = from, len = this.length; i < len; i++) {
       if (this[i] === elem) {
         return i;
   ...
   

3. indexOf(element)

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

4. indexOf(elt /*, from*/)

   Array.prototype.indexOf = function(elt ) {
     var len = this.length;
     var from = Number(arguments[1]) || 0;
     from = (from < 0) ? Math.ceil(from) : Math.floor(from);
     if (from < 0) {
       from += len;
     for (; from < len; from++) {
       if (from in this && this[from] === elt) {
   ...
   

5. indexOf(elt /*, from*/)

   Array.prototype.indexOf = function(elt )
       var len = this.length;
       var from = Number(arguments[1]) || 0;
       from = (from < 0)
            ? Math.ceil(from)
            : Math.floor(from);
       if (from < 0)
         from += len;
   ...
   

6. indexOf(given, strict)

   Array.prototype.indexOf = function(given, strict) {
     var result = null;
     this.each(function(elem, idx) {
       if (strict) {
         if (elem === given) {
           result = idx;
           return false;
       else {
         if (elem == given) {
           result = idx;
           return false;
     })
     return result;
   

7. indexOf(item)

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

8. indexOf(item)

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

9. indexOf(item,from)

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