JSFiddle - React, Tailwind, and code Playground

JavaScript

var data = '{"2015:ATM01": {"volume": "2620000","count": "78"},"2015:PIN_PURCHASE01": {"volume": "5162305","count": "101"},"ALL:PIN_PURCHASE01": {"volume": "5162305","count": "101"},"ALL:DIRECT_DEPOSIT01": {"volume": "32752700","count": "50" }}';

var JSONArray=JSON.parse(data);

for(var k in JSONArray){
    console.log("key is  is.... "+k);
    console.log("voulume is.... "+JSONArray[k].volume);
}