JSFiddle - React, Tailwind, and code Playground

by Chris Nitsas

HTML

<pre id="result"></pre>

JavaScript

let 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;
}

// output
let result = document.getElementById('result');
result.innerHTML = JSON.stringify(Counter(list), null, 2);