How can I spread array elements into an object as the keys, and define some value for them?

Question

Let say I have an array:

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

I want to create an object like this:

{ 'a': true, 'b': true, 'c': true}

How can I do this?

const obj = {...arr: true} 

did not work

Answer 1

Using Array#reduce:

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

const res = arr.reduce((acc, key) => ({ ...acc, [key]: true }), {});

console.log(res);