Typescript Intersection and Union Types Combined

Today I learned about intersection and union types in Typescript.

If you’re using Typescript, you probably know about union types | and intersection types &

I was doing a code review today and saw something interesting. I saw this (because this is a private repo I’ve change some of the variable names)

export type Example = {
  otherPropId: 'start'
  propId: string
  mode: Mode
  x: number
  y: number
} & (
  | {
       shape: 'circle'
       r: number
    }
  | {
       shape: 'rect' 
       w…