How to override type properties in TypeScript

Question

For example, I have

type Line = {
  start: Point;
  end: Point;
  color: string; //'cyan'/'aquablue'/...
}

But now I want to create new line type on the base of Line, so that it stores color as number:

type HexColorLine = Point & {
  color: number;
}

Now I expect the HexColorPoint type be equal to

{
  start: Point;
  end: Point;
  color: number;
}

But it equals to

{
  start: Point;
  end: Point;
  color: string | number;
}

Is there a way to override but not extend the prop type with some short syntax? Do i really have to define entirely new type for this?

Answer 1

Create a helper type:

type Overwrite<T, U> = Pick<T, Exclude<keyof T, keyof U>> & U;

Usage:

type HexColorLine = Overwrite<Line, { color: number }>