Generic object rest variables and parameters

TypeScript 3.2 also allows destructuring a rest binding from a generic variable. This is achieved by using the predefined Pick and Exclude helper types from lib.d.ts, and using the generic type in question as well as the names of the other bindings in the destructuring pattern.

function excludeTag<T extends { tag: string }>(obj: T) {
    let { tag, ...rest } = obj;
    return rest;  // Pick<T, Exclude<keyof T, "tag">>
}
const taggedPoint = { x: 10, y: 20, tag: "point" };
const point = excludeTag(taggedPoint);  // { x: number, y: number }