javascript - Swap key with value in object

Question

I have an extremely large JSON object structured like this:

{A : 1, B : 2, C : 3, D : 4}

I need a function that can swap the values with keys in my object and I don't know how to do it. I would need an output like this:

{1 : A, 2 : B, 3 : C, 4 : D}

Is there any way that I can do this would manually created a new object where everything is swapped?
Thanks

Answer 1

function swap(json){
  var ret = {};
  for(var key in json){
    ret[json[key]] = key;
  }
  return ret;
}

Example here FIDDLE don't forget to turn on your console to see the results.

---

ES6 versions:

static objectFlip(obj) {
  const ret = {};
  Object.keys(obj).forEach(key => {
    ret[obj[key]] = key;
  });
  return ret;
}

Or using Array.reduce() & Object.keys()

static objectFlip(obj) {
  return Object.keys(obj).reduce((ret, key) => {
    ret[obj[key]] = key;
    return ret;
  }, {});
}

Or using Array.reduce() & Object.entries()

static objectFlip(obj) {
  return Object.entries(obj).reduce((ret, entry) => {
    const [ key, value ] = entry;
    ret[ value ] = key;
    return ret;
  }, {});
}