SaschaHeyer

let beerId = 10;
{
  let beerId = 42;
}
console.log(beerId);
// result 12

SaschaHeyer

{
  let beerId = 42;
}
console.log(beerId)
// result: refrence error

SaschaHeyer

() => { statements }

SaschaHeyer

parameter => { statements }

SaschaHeyer

(firstParameter, secondParameter) => { statements }

SaschaHeyer

const name = (parameters) => {
    statements
}

SaschaHeyer

var addBeer = function(name, category = 'Pils') {
  console.log(name + ' ' + category);
};

addBeer(); // output: undefined Pils
addBeer('Bitburger'); // output: Bitburger Pils
addBeer('Bolten', 'Alt'); // output: Bolten Alt

SaschaHeyer

var getBeerPrice = function(price, tax = price * 0.09){
  console.log(price + tax);
};

getBeerPrice(5); // output: 5.45

SaschaHeyer

function sum(…numbers) {
  var result = 0;
  numbers.forEach(function (number) {
    result += number;
  });
  return result;
}

console.log(sum(1)); // 1
console.log(sum(1, 2, 3, 4, 5)); // 15

SaschaHeyer

var name = 'Beer';
var stock = 42;
var product = {
  name,
  stock,
  reduceStock(){
    this.stock--;
  }
}