Default destructed function parameters in one object in JavaScript

Question

is there a possibility to access ALL destructed function parameters in one object?

So I have this function head:

function coolFunctionName({test1 = "foo", test2 = "bar"})

I want to access them in one object. arguments doesn't work, because there aren't stored the default parameters which doesn't have a value in function call.

Is there a good and clean way to do that?

EDIT: I don't need the destructed parameters. I just want to have all of them in one object.

Then don't destructure it in the argument list, rather receive it in (args = {}) object, and do what you have now inside the function body? — Arup Rakshit, Sep 14 '18 at 14:31
That you can do when destructuring inside the body also. In one word, what you asked is not yet possible in current JS . — Arup Rakshit, Sep 14 '18 at 14:39
Destructuring allows to target individual variables, and it allows to give every target a default value. It does *not* create a new object, you will have to do that yourself. You cannot [destructure and construct an object literal at the same time](https://stackoverflow.com/q/25553910/1048572). — Bergi, Sep 14 '18 at 14:44

score 2 · Accepted Answer · answered Sep 14 '18 at 15:01

Inspired from Faly's answer I think I've got the "cleanest" solution:

function coolFunctionName(options = {}){
    options = Object.assign({
        test1: "foo",
        test2: "bar
    }, options);
}

I have the parameter in one object and I have not to write multiple value names. I'm not happy about that because it's not in the function head but it's the best solution I've found.

Naga Sai A · Answer 2 · 2018-09-14T15:15:10.267

0

To achieve expected result, use below option of setting default value inside function

function coolFunctionName(x){
  x.test1 = x.test1 || 'foo'
  x.test2 = x.test2 || 'bar'
  console.log(x)
}
let z ={}
coolFunctionName(z);
let y ={test1:"zzz", test2:"yyy"}
coolFunctionName(y);

codepen- https://codepen.io/nagasai/pen/KxBmod?editors=1011

edited Sep 14 '18 at 15:15

answered Sep 14 '18 at 14:49

Naga Sai A

9,949
1
15
34

Nope, the values are ALWAYS `test1: "foo"` and `test2: "bar"`. – Vincent Hoch-Drei Sep 14 '18 at 14:56
@VincentHoch-Drei, there should be a check to check if parameters have any values or not and then assign default values, updated my codepen - https://codepen.io/nagasai/pen/KxBmod?editors=1011 and answer – Naga Sai A Sep 14 '18 at 15:01
@VincentHoch-Drei, updated and made it simple and works in all browsers, if you use Object.assign, you may need to use polyfill - https://github.com/mozilla-services/react-jsonschema-form/issues/206 – Naga Sai A Sep 14 '18 at 15:14

score -1 · Answer 3 · answered Sep 14 '18 at 14:33

-1

All you can do is:

function coolFunctionName({test1 = "foo", test2 = "bar"}) {
    let arguments = { test1, test2 };
    /* Do whatever you want with arguments */
}

answered Sep 14 '18 at 14:33

Faly

12,529
1
16
34

1

Can the persons who downvoted explains the downvotes ? – Faly Sep 14 '18 at 14:38
That's an idea but I have to write every parameter name twice. That's not really clean. – Vincent Hoch-Drei Sep 14 '18 at 14:39
3

There's no other ideas – Faly Sep 14 '18 at 14:40
I did not downvote this, but - I would assume that it was downvoted because a) There is no evidence of research done, and b) This answer is not useful as it does not directly address, explain, or answer the OP's question. Please do some work before you post an answer. – AlexanderGriffin Sep 14 '18 at 14:41
Down-voting without explaining why is just a poor and pathetic practice – Faly Sep 14 '18 at 14:45

Default destructed function parameters in one object in JavaScript

3 Answers3