How to assign a value to nested object by varying key?

Question

I have nested objects, for example:

var a = {b: {c: {d: 1}}};

and a dynamic key:

var field = "b.c.d"

I need to change a value at object a by key b.c.d. Nesting level of object and key can vary. The only thing which works for me is:

eval("a."+field+"=2"); -> it means a.b.c.d = 2;

But it's ugly. Is there a better way?

Answer 1

You can try following using a recursive function

var a = {b: {c: {d: 1}}};
var field = "b.c.d";
var value = 2;

function updateObject(obj, key, val){
  if(obj) {
    if(key.includes(".")) {
      var keys = key.split(".");
      updateObject(obj[keys.shift()], keys.join("."), val);
    } else if (obj.hasOwnProperty(key)) obj[key] = val;
  }
}

updateObject(a, field, value);

console.log(a);