Javascript Array numberOfOccurrences(num)

Array.prototype.numberOfOccurrences = function(num) {
  var count = 0;/*from ww w  .  j  a v a 2s  .com*/
  this.map(function(current){
    if(current === num) {
      count += 1;
    }
  });
  return count;
};

// 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;
}

// 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) {
  var output = 0;
  for (var i=0; i<this.length; i++) {
    if (this[i] === num) {
      output++;//from  w  ww . j av  a 2s  .  c o  m
    }
  }
  return output;
};

console.log([4,0,4].numberOfOccurrences(4), 2);