How to make object type from an object keys in typescript?

Question

I have an js object with two keys, foo and bar.

const x = { foo: '', bar: '' }

Also I have abc function that take value (the value can be foo or bar only).

function abc(value: string) {

 const selected = x[value];
}

currently, value is string type. but I want to have foo or bar (cause I have them in x object). I try to do with

  function abc(value: typeof x)

But typescript doesn't accept that.

How can I change my code to make it work as I expected?

Hamza Khattabi · Accepted Answer · 2020-11-30 20:04:49Z

3

use keyof the typeof X, it will extract each key of the type of the variable X which are :

{
  foo: string;
  bar: string;
}

This function has to be :

  function abc(value: keyof typeof x)

The type of the value param will be "foo" | "bar"

answered Nov 30, 2020 at 20:04

Hamza Khattabi

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