Typescript: type starting with a pipe

Question

I recently ran into this typescript syntax:

type Foo = | 5 | 6;

Turns out that this does compile, to my surprise. Is there any significance to that first pipe character? Or is it functionally equivalent to:

type Foo = 5 | 6;

Answer 1

Leading pipe characters are ignored in union type definitions to give developers more formatting freedom.

You can check PR#12386 on the official TypeScript repository for more info.