Is there a Javascript function similar to the Python Counter function?

Question

I am attempting to change a program of mine from Python to Javascript and I was wondering if there was a JS function like the Counter function from the collections module in Python.

Syntax for Counter

from collection import Counter list = ['a', 'b', 'c', 'b', 'a', 'b', 'c', 'a', 'a', 'a'] counter = Counter(list) print counter 

output

Counter({'a':5, 'b':3, 'c':2}) 

Answer 1

DIY JavaScript solution:

var list = ['a', 'b', 'c', 'b', 'a', 'b', 'c', 'a', 'a', 'a'];  function Counter(array) {   var count = {};   array.forEach(val => count[val] = (count[val] || 0) + 1);   return count; }  console.log(Counter(list)); 

JSFiddle example

Update:

Alternative that uses a constructor function:

var list = ['a', 'b', 'c', 'b', 'a', 'b', 'c', 'a', 'a', 'a'];  function Counter(array) {   array.forEach(val => this[val] = (this[val] || 0) + 1); }  console.log(new Counter(list)); 

JSFiddle example