JSFiddle - React, Tailwind, and code Playground

JavaScript

var arr = ['a','b','c','d','d','e','a','b','c','f','g','h','h','h','e','a'];
var obj = {};
for(var a in arr){
	var temp = arr[a];
	if(typeof obj[temp] == "undefined"){
  	obj[temp] = 0;
  }
  obj[temp]++;
}

console.log(obj);