Nodejs Array Item Occurrence numberOfOccurrences(num)

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(num) {
    return this.filter(function(item){return item==num;}).length;
}

Related

1. 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]
   

2. 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];
   ...
   

3. 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;
   ...
   

4. 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);
   ...
   

5. numberOfOccurrences(n)

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

6. numberOfOccurrences(num)

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

7. numberOfOccurrences(number)

   Array.prototype.numberOfOccurrences = function(number) {
     return this.reduce(function (previous, current) {
       return (current === number) ? ++previous : previous;
     }, 0);
   };
   

8. numberOfOccurrences(search)

   Array.prototype.numberOfOccurrences = function (search) {
     return this.filter(function (num) { return search === num }).length;
   

9. numberOfOccurrences(search)

   Array.prototype.numberOfOccurrences = function(search) {
     return this.filter( function(num){ return search === num } ).length;