How can I dynamically set an objects keys to a variable using Javascript?

Question

export function getNoteKeys() {
    const notesObject = {}
    for (let i = 0; i < localStorage.length; i++) {
        const key = localStorage.key(i)
        const value = localStorage[key]
        notesObject[key] = value
    }
    store.dispatch(SetActionForNotes(_.values(notesObject).sort(function(a, b) {
        return a > b
    })))
}

The current output I am getting for the above code is this...

{0: "a", 1: "b", 2: "c", 3: "d"}

The problem with this is that when I convert this to an array I do not have the ability to continue to uniquely identify each object after an item is removed, because the indexes of the items change if one is removed.

I want to set each key set to an id for every value retrieved. I have unique keys already set in localstorage, and I need them to uniquely identify each note in a list. I have tried many different ways and cannot figure this out.

As an example of what I am trying to do...

const obj = [{id: 1, value: "a"}, {id: 2, value: "b"}...]

Are you trying to use dynamic object keys, or just trying to map each key-value pair from localStorage to a new object shape? Your example output obj doesn't match what the code is doing and isn't a valid JS object. It's unclear what you are asking for. Also, the sort function comparator should return a number value, i.e. [-1, 0, 1], not a boolean to indicate sorting order. — Drew Reese
– Drew Reese, Commented Aug 3, 2021 at 6:29
{[{id: 1}, {value: "a"}], [{id: 2}, {value: "b"}]...} isn't valid object syntax, are you trying to get something like [{ id: 1, value: 'a' }, { id: 2, value: 'b' }, ...] in an array? — Drew Reese
– Drew Reese, Commented Aug 3, 2021 at 6:45
@DrewReese yes that is what I am aiming for. Ill edit my question so it will be correct. — Arcanus
– Arcanus, Commented Aug 3, 2021 at 6:47
Can you include also an example localStorage value so we can see where you're starting from? — Drew Reese
– Drew Reese, Commented Aug 3, 2021 at 6:48

Toshkata Tonev · Accepted Answer · 2021-08-03 07:30:11Z

1

Not sure what exactly is you purpose, but this will do the transformation you want.

Object.keys(localStorage).reduce((acc,key)=>{
  return[...acc,{id:key,value:localStorage[key]}]
},[])

edited Aug 3, 2021 at 7:30

answered Aug 3, 2021 at 6:47

Toshkata Tonev

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Arcanus Over a year ago

I am assuming value:asd[key] was added in error, your answer worked once I removed asd

Drew Reese · Accepted Answer · 2021-08-03 07:54:51Z

1

It seems that localStorage is an object (versus array), and if so you can also use Object.entries and map the array of key-value pairs into [{ id: 1, value: 'a' }, { id: 2, value: 'b' }, ...].

Object.entries(localStorage).map(([id, value]) => ({ id, value }))

const localStorage = {
  0: 'a',
  1: 'b',
  2: 'c',
};

const res = Object.entries(localStorage).map(([id, value]) => ({ id, value }));

console.log(res);

Though since objects are just associative arrays of key-value pairs, it works with arrays as well.

const localStorage = ['a', 'b', 'c'];

const res = Object.entries(localStorage).map(([id, value]) => ({ id, value }));

console.log(res);

edited Aug 3, 2021 at 7:54

answered Aug 3, 2021 at 7:48

Drew Reese

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