typing function ts 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: typescript function type

interface Date {
  toString(): string;
  setTime(time: number): number;
  // ...
}

Example 3: simple function in typescript

// Named function

//function with type as number
function add(x: number, y: number): number {
  // return sum of numbers entered as params
  return x + y;
}

// Anonymous function

// variable to call and define function
let myAdd = function (x: number, y: number): number {
  // return sum of numbers entered as params
  return x + y;
};