TypeScript Type-safe Omit Function

Question

I want to replicate lodash\'s _.omit function in plain typescript. omit should return an object with certain properties removed specified via parameter

Answer 1

If we limit the type of keys to string [],It works. But it does not seem to be a good idea.Keys should be string | number | symbol[];

function omit(
  obj: T,
  ...keys: K[]
): { [k in Exclude]: T[k] } {
  let ret: any = {};
  Object.keys(obj)
    .filter((key: K) => !keys.includes(key))
    .forEach(key => {
      ret[key] = obj[key];
    });
  return ret;
}
const result = omit({ a: 1, b: 2, c: 3 }, 'a', 'c');
// The compiler inferred result as 
// {
//   b: number;
// }