convert set to object

Question

I have a set which needs to be converted into an object with the set's unique values as the object keys and an empty string as each element's value in the object.

Here is the set I'm working with:

const uom = new Set(['inches', 'centimeters', 'yards', 'meters']);

I've tried this:

const uomObj = {...[...uom]};
console.log(uomObj);

Which yields this:

Object {
  "0": "inches",
  "1": "centimeters",
  "2": "yards",
  "3": "meters",
}

but that does not match the desired result of:

Object {
  "inches": "",
  "centimeters": "",
  "yards": "",
  "meters": "",
}

Can this be achieved with an ES6 approach? If so, how?

Answer 1

You can use Array.from with a mapping function to convert each value inside your set into an object and then use Object.assign() with the spread syntax to merge the array of objects into a single resulting object like so:

const uom = new Set(['inches', 'centimeters', 'yards', 'meters']);
const res = Object.assign(...Array.from(uom, v => ({[v]:''})));
console.log(res);

Answer 2

Here's one way:

[...uom].reduce((o, u) => {
  o[u] = '';
  return o;
}, {})

Answer 3

Create an object, then loop over the values in the set and create a property for each one. The reduce method is probably the most compact way to do that.

const uom = new Set(['inches', 'centimeters', 'yards', 'meters']);
const result = Array.from(uom).reduce( (a,c) => { a[c]=""; return a; }, {});
console.log(result);