JSFiddle - React, Tailwind, and code Playground

JavaScript

var foo = [
    {"width":128.90663423245883,"height":160,"X":0,"Y":140},
    {"width":277.0938568683375,"height":263,"X":128.90663423245883,"Y":37},
    {"width":264.8267031014369,"height":261,"X":277.0938568683375,"Y":39},
    {"width":229.14003389179788,"height":60,"X":264.8267031014369,"Y":240},
    {"width":10.032771905968888,"height":177,"X":229.14003389179788,"Y":123}
];

function count(stack) {
	var totWidth = 0;
  stack.forEach(function(element) {
    totWidth = totWidth+element.width;
	});
  return totWidth;
}

count(foo);