Javascript get Object property Name

Question

I passed the following object:

var myVar = { typeA: { option1: "one", option2: "two" } }

I want to be able to pull out the key typeA from the above structure.

This value can change each time so next time it could be typeB.

So I would like to know if there is a way for me to do something like the following pseudo code:

var theTypeIs = myVar.key();

This way when I can pass this object and I can pull out the first value of the object, in this case it is typeA and then based on that I can do different things with option1 and option2.

Answer 1

If you know for sure that there's always going to be exactly one key in the object, then you can use Object.keys:

theTypeIs = Object.keys(myVar)[0];

Answer 2

Like the other answers you can do theTypeIs = Object.keys(myVar)[0]; to get the first key. If you are expecting more keys, you can use

Object.keys(myVar).forEach(function(k) {
    if(k === "typeA") {
        // do stuff
    }
    else if (k === "typeB") {
        // do more stuff
    }
    else {
        // do something
    }
});

Answer 3

If you want to get the key name of myVar object then you can use Object.keys() for this purpose.

var result = Object.keys(myVar); 

alert(result[0]) // result[0] alerts typeA