JSFiddle - React, Tailwind, and code Playground

HTML

<span id='valX'>x</span><br>
<span id='valY'>y</span>

JavaScript

var arr = {
  "0":["2","2","2","2"],
  "1":["2","0"],
  "28":["0","0","0","0"],
  "29":["0","2"],
  "30":{"3":"2","0":"2","14":"2","6":"1"},
  "-2":{"8":"2","2":"1","3":"1"},
  "36":{"27":"2","15":"1","16":"1"},
  "-83":{"67":"2"},
  "194":{"214":"2"},
  "178":{"192":"2"},
  "127":{"145":"2"},
  "55":{"147":"2"},
  "47":{"21":"1"},
  "40":{"19":"1"},
  "37":{"19":"1"},
  "65":{"17":"1"}};

var xMin = Number.MAX_SAFE_INTEGER, 
    xMax = Number.MIN_SAFE_INTEGER, 
    yMin = Number.MAX_SAFE_INTEGER, 
    yMax = Number.MIN_SAFE_INTEGER;

for (var x in arr) {
  if (xMin > x*1)
    xMin = x;
  if (xMax < x*1)
    xMax = x;
  if (Array.isArray(arr[x])) {
    if (yMin > 0)
      yMin = 0;
    if (yMax < arr[x].length)
      yMax = arr[x].length;
  } else {
    for (var y in arr[x]) {
     if (yMin > y*1)
      yMin = y;
     if (yMax < y*1)
      yMax = y;
    }
  }
}
alert(xMin+' <= x <= '+xMax+"\n"+yMin+' <= y <= '+yMax);