What does the pipe(|) mean in typescript?

Question

While browsing some typescript code of @ng-bootstrap I have found pipe(|) operator.

export declare const NGB_PRECOMPILE: (typeof N         


        

Answer 1

The pipe represents 'or'. So in this context it says that either of the declared types is allowed. Perhaps it is easy to understand a union with primitive types:

let x: (string | number);

x = 1; //ok
x = 'myString'; //ok
x = true; //compilation error for a boolean