typescript return type of function as type code example

Example 1: get function return type typescript

type return_type = ReturnType<() => string>; // string
// or
function hello_world(): string {
  return "hello world";
}
type return_type = ReturnType<typeof hello_world>; // string

Example 2: function with return type in angular

greet() : number {
    return "Hello, " + this.greeting;
}