Nodejs Array Index indexFor(item)

Method Source Code

Array.prototype.indexFor = function( item ) {
    var output=-1;
    for (var i = 0 ; i < this.length ; i ++) {
        if (this[i]===item) {
            output= i; /*  ww  w  .  j a v a 2s.  com*/
            break;
        }
    }
    return output; 
};
[2,3,5,5,6,8,9,10,22,49].indexFor("a");

Related

1. indexByAction(predicate)

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

2. indexByKey(keyName)

   Array.prototype.indexByKey = function(keyName) {
     return this.reduce( (obj, el) => {
       obj[ el[keyName] ] = el;
       return obj;
     }, {});
   };
   

3. indexContains(word)

   Array.prototype.indexContains = function(word) {
       for (var idx = 0; idx < this.length; idx++) {
           var test = this[idx];
           if (test.indexOf(word) >= 0 || word.indexOf(test) >= 0) {
               return idx;
       return -1;
   };
   ...
   

4. indexOf || (Array.prototype.indexOfindexOf(searchElement)

   "use strict";
   Array.prototype.indexOf || (Array.prototype.indexOf=function indexOf(searchElement) {
       var array = this,
           length = array.length,
           index = 0;
       for (index = 0; index < length; ++index) {
           if (array[index] === searchElement) {
               return index;
       return -1;
   });
   

5. indexOf( v, b, s )

   Array.prototype.indexOf = function( v, b, s ) {
     for( var i = +b || 0, l = this.length; i < l; i++ ) {
       if( this[i]===v || s && this[i]==v ) { return i; }
     return -1;
   };
   

6. indexOf( value )

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

7. indexOf( value )

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