JSFiddle - React, Tailwind, and code Playground

JavaScript

var collection = [{
  "Name": "Charlie",
  "ID": "13"
}, {
  "Name": "Emma",
  "ID": "9"
}, {
  "Name": "Bob",
  "ID": "5"
}];

total = 0, //set a variable that holds our total
  id = collection, //reference the element in the "JSON" aka object literal we want
  i = 0;
for (i = 0; i < id.length; i++) { //loop through the array
  total += id[i].ID; //Do the math!
}
console.log(total); //display the result