diff.js

function difference(obj1, obj2) {
  const ret = {
    new: {},
    removed: {},
    diff: {}
  }
  const keys1 = Object.keys(obj1);
  const keys2 = Object.keys(obj2);
  for (let k of keys1) {
    if (keys2.indexOf(k) === -1) {
      ret.removed[k] = obj1[k]
    }
    const v1 = JSON.stringify(obj1[k]);
    const v2 = JSON.stringify(obj2[k]);
    if (v1 !== v2) {
      ret.diff[k] = {
        'old': obj1[k],
        'new': obj2[k]
      }
    }
  }
  for (let k of keys2) {
    if (keys1.indexOf(k) === -1) {
      ret.new[k] = obj2[k];
    }
  }
  return ret;
}