Nodejs Array Item Occurrence numberOfOccurrences(el)

Method Source Code

// The numberOfOccurrences function must return the number of occurrences of an element in an array.

// var arr = [0,1,2,2,3];
// arr.numberOfOccurrences(0) === 1;
// arr.numberOfOccurrences(4) === 0;
// arr.numberOfOccurrences(2) === 2;
// arr.numberOfOccurrences("a") === 0;

Array.prototype.numberOfOccurrences = function (el) {
  var count = 0;/*w  w  w . j a  v  a  2s .c om*/
  this.forEach(function (item) {
    if (item === el) count++;
  });
  return count;
}

Related

1. numberOfOccurrences( arg )

   Array.prototype.numberOfOccurrences = function( arg ) {
     var num = 0;
     this.forEach( function( e ){
       if ( arg === e ) { num++; }
     });
     return num;
   };
   var arr = [0,1,2,2,3,"a"];
   console.log( arr.numberOfOccurrences("a") );
   ...
   

2. numberOfOccurrences(arr)

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

3. numberOfOccurrences(chr)

   Array.prototype.numberOfOccurrences = function(chr) {
     return this.filter(function(x){ return x == chr; }).length;
   

4. numberOfOccurrences(desVal)

   Array.prototype.numberOfOccurrences = function(desVal) {
     var counter = 0;
     this.forEach(function(value){
       if(value === desVal){
         counter++;
     });
     return counter;
   };
   ...
   

5. numberOfOccurrences(elem)

   Array.prototype.numberOfOccurrences = function(elem) {
     let obj = {};
     this.forEach(elem => elem in obj ? obj[elem]++ : obj[elem] = 1);
     return obj[elem] === undefined ? 0 : obj[elem]
   

6. numberOfOccurrences(i)

   Array.prototype.numberOfOccurrences = function(i) {
     var total = 0;
     this.filter(function (x) {
       if (i === x)
         total++;
     });
     return total;
   };
   var arr = [0,1,2,2,3];
   ...
   

7. numberOfOccurrences(item)

   Array.prototype.numberOfOccurrences = function(item) {
   var drr = []; 
   var i = 0 ;
      for(i = 0 ; i < this.length ; i++) {
          if(item=== this[i]){
              drr.push(this[i]); 
       return drr.length;
   ...
   

8. numberOfOccurrences(item)

   var arr = [4, 0, 4];
   Array.prototype.numberOfOccurrences = function(item) {
     tmp = 0;
     for(var i=0; i<this.length; i++){
       if (item == this[i]) {
         tmp ++;
     console.log(tmp);
   ...