Arrow function

 hello = function() {

  return "Hello World!";

}

⮟

hello = () => {

  return "Hello World!";

}

⮟

hello = () => "Hello World!";

"If the function has only one statement, and the statement returns a value, you can remove the brackets and the return keyword"

"This works only if the function has only one statement."

hello = (val) => "Hello " + val;

If you have parameters, you pass them inside the parentheses

hello = val => "Hello " + val;

if you have only one parameter, you can skip the parentheses as well