How to add TypeScript types to destructured parameters using spread syntax?
My bad, the answer is as simple as:
const add = ([x, ...xs]: number[]) => { if (x === undefined) return 0 else return x + add(xs)}console.log(add([1, 2, 3])); //=> 6add(["", 4]); // errorOriginal answer:
You can do this:
const add: (nums: number[]) => number = ([x, ...xs]) => { if (x === undefined) return 0 else return x + add(xs)}You can also use a type alias:
type AddFunction = (nums: number[]) => number;const add: AddFunction = ([x, ...xs]) => { ...}