how to set return type in typescript code example

Example 1: typescript function type

// define your parameter's type inside the parenthesis
// define your return type after the parenthesis

function sayHello(name: string): string  {
  console.log(`Hello, ${name}`!);
}

sayHello('Bob'); // Hello, Bob!

Example 2: 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 3: function with return type in angular

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

Example 4: typescript annotate return type

function add(x: number, y: number): number {
  return x + y;
}