How to modify all properties of an object in a functional way

Question

I need to create a function which create a new object with all properties of in set to true, the function should create a new object.

How to do it with vanilla js? I can use deconstruction and latest JS.

   const in = {
        ida:true,
        idb:false,
        idc:false,
        ide:true
    }

result wanted

const out = {
    ida:true,
    idb:true,
    idc:true,
    ide:true
}

Possible duplicate of [Set all Object keys to false](https://stackoverflow.com/questions/40836239/set-all-object-keys-to-false) — GalAbra, Jun 05 '18 at 14:41
Possible duplicate of [Iterate through object properties](https://stackoverflow.com/questions/8312459/iterate-through-object-properties) — sander, Jun 05 '18 at 14:41
"How to do it with vanilla js?" — Use an immutable library. Don't reinvent the wheel. — Quentin, Jun 05 '18 at 14:42
There is no need for a library @Quentin, is basic js functionality. — J. Pichardo, Jun 05 '18 at 14:43
@J.Pichardo — Only if none of your properties have values which are objects. — Quentin, Jun 05 '18 at 14:44

score 4 · Accepted Answer · answered Jun 05 '18 at 14:42

4

Well, you could use Object.keys and the spread operator to accomplish this:

const input = {
  ida: true,
  idb: false,
  idc: false,
  ide: true
}

const out = Object.keys(input).reduce((acc, key) => ({...acc, [key]: true}), {});

console.log(out)

answered Jun 05 '18 at 14:42

J. Pichardo

3,077
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score 2 · Answer 2 · answered Jun 05 '18 at 14:42

2

You could map all keys with an new object and false as value. Later assign them to a single object.

const
    inO = { ida: true, idb: false, idc: false, ide: true },
    outO = Object.assign(...Object.keys(inO).map(k => ({ [k]: true })));
    
console.log(outO);

answered Jun 05 '18 at 14:42

Nina Scholz

376,160
25
347
392

thanks, but I this warning Expected at least 1 arguments but got 0 or more any idea? – Radex Jun 05 '18 at 14:45
I am using typescript – Radex Jun 05 '18 at 14:47
With destructuring I find it more elegant to use { ...Object.keys } instead of Object.assign – Logar Jun 05 '18 at 14:49
@Radex, sorry, can not help with *typescript*. – Nina Scholz Jun 05 '18 at 14:50
@Radex in what function call are you getting that error? – J. Pichardo Jun 05 '18 at 14:55
@NinaScholz right, hard to get it working here. Another solution is reduce : `Object.keys(inO).reduce((m, k) => ({...m, [k]: true}), {})` – Logar Jun 05 '18 at 14:56
1

@Logar that's the same as my answer :) – J. Pichardo Jun 05 '18 at 14:57
1

@J.Pichardo ah yeah, just noticed :) – Logar Jun 05 '18 at 14:57

score 0 · Answer 3 · answered Jun 05 '18 at 14:43

0

You can use a for..in loop which iterates over the keys of an object:

function setTrue(obj) {
  for (k in obj) obj[k] = true;
}

const o = {
  ida: true,
  idb: false,
  idc: false,
  ide: true
}

setTrue(o);
console.log(o);

answered Jun 05 '18 at 14:43

Sebastian Speitel

7,166
2
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How to modify all properties of an object in a functional way

3 Answers3