typescript function reference type 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: types function typescript

interface Param {
    title: string;
    callback: function;
}

Example 3: typescript annotate return type

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