Add a child to a JavaScript object with a variable name

Question

Let's say I have a blank JavaScript object:

myObject {}

And I also have a variable:

var myChildObject = this.name.split('.')[1];

For the sake of an example, let's say that myChildObject equals "FooBar". Now, I want to add a child object to myObject with the name of "FooBar", only we can't hard code "FooBar". We have to use the variable name myChildObject.

I tried this:

myObject.appendChild(myChildObject);

That doesn't work.

The goal is this:

{  
   "myObject":{  
      "FooBar":{  
         "thing1":25,
         "thing2":6
      },
      .....
}

But I need to build the entire thing dynamically, without the names (other than the root) being known ahead of time.

Right @Madara. I want to add a new object with the name of "FoBar" — Casey Crookston, Jan 23 '17 at 19:35
Possible duplicate of [javascript "associative" array access](http://stackoverflow.com/questions/2524413/javascript-associative-array-access) — dave, Jan 23 '17 at 19:36
JavaScript object has key value pair. What do you want as the key for *FooBar* — Mustafa Mamun, Jan 23 '17 at 19:38
Your goal is not valid JavaScript. Objects need a key and a value. Do you want an array? `{MyObject: ["FooBar"]}`? — Madara's Ghost, Jan 23 '17 at 19:38
@dave -- I don't see how my question and that question are even close to the same thing. — Casey Crookston, Jan 23 '17 at 19:39
@CaseyCrookston note that your "goal" is invalid JS. What value does "FooBar" map to? — Whymarrh, Jan 23 '17 at 19:40

score 2 · Accepted Answer · answered Jan 23 '17 at 19:38

An object is a "key value" type of thing, a little bit like a Map in Java. have you tried something like this:

let myObject = {};
let myChildObject = "fooBar";
myObject[myChildObject] = {};

This way you have a "fooBar" key for your Object... now you have to decide what you want the value to be for that key.

Mustafa Mamun · Answer 2 · 2017-01-23T19:43:57.113

1

var myObject = {};
var myChildObject = this.name.split('.')[1];
myObject[myChildObject] ={  
     "thing1":25,
     "thing2":6
  };

edited Jan 23 '17 at 19:43

answered Jan 23 '17 at 19:40

Mustafa Mamun

2,591
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Thank you, but, the thing is, FooBar can not be hard coded. I don't know the name of FooBar ahead of time, so it MUST be a variable – Casey Crookston Jan 23 '17 at 19:42
Ok, we are on to something now! Lemme play with this and I'll BRB. – Casey Crookston Jan 23 '17 at 19:46

score 1 · Answer 3 · answered Jan 23 '17 at 19:43

Objects can only have key value pair. You cannot use one without other. If you don't want to assign a value then simply give undefined. If you don't know the name of the property then you can simply use the array type notation for an object "[]". Refer to code below

var myObject = {};
var myChildObject = this.name.split('.')[1];

myObject[myChildObject] = undefined;

console.log(myObject.hasOwnProperty(myChildObject)); // true

score 0 · Answer 4 · answered Jan 23 '17 at 19:45

0

I'd say

for(var key in myChildObject) {
  myObject[key] = myChildObject[key]
}

answered Jan 23 '17 at 19:45

ValLeNain

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score 0 · Answer 5 · answered Jan 23 '17 at 19:46

0

No idea what your question means but myObject["foobar"] might be what you are looking for

answered Jan 23 '17 at 19:46

Booboobeaker

86
6

Add a child to a JavaScript object with a variable name

5 Answers5