Javascript count duplicates and uniques and add to array

Question

I\'m trying to count duplicates in an array of dates and add them to a new array.

But i\'m only getting the duplicates and the amount of times they exist in the array. <

Answer 1

You can use reduce and return object

var ar = ['a', 'a', 'b', 'c', 'c'];
var result = ar.reduce(function(r, e) {
  r[e] = (r[e] || 0) + 1;
  return r;
}, {});

console.log(result)

You can also first create Object and then use forEach add properties and increment values

var ar = ['a', 'a', 'b', 'c', 'c'], result = {}
ar.forEach(e => result[e] = (result[e] || 0)+1);
console.log(result)