Nodejs Array Index indexByKey(keyName)

Method Source Code

Array.prototype.indexByKey = function(keyName) {

  return this.reduce( (obj, el) => {
    obj[ el[keyName] ] = el;/*from  ww  w  .j av a 2 s .com*/
    return obj;
  }, {});

};

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. 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;
   };
   ...
   

3. indexFor(item)

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

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;
   };