Using spread syntax and new Set with typescript

Question

I am using following code to get unique numbers:

let uniques = [ ...new Set([1, 2, 3, 1, 1]) ]; // [1, 2, 3]

Typescript, on the other hand, reports the following error: The array type 'Set' does not exist. Could someone tell me what is wrong here, as I am not a typescript ninja?

Answer 1

This seems to be a typescript ES6 transpilation quirk . The ... operator should work on anything that has an iterator property, (Accessed by obj[Symbol.iterator]) and Sets have that property.

To work around this, you can use Array.from to convert the set to an array first: ...Array.from(new Set([1, 2, 3, 1, 1])).