Cygra

var foo = () => arguments[0];
foo(); // arguments is not defined

function bar() {
  return arguments[0];
}
bar(); // undefined

Cygra

let arr = (...params) => console.log(params);

arr(1, 2, 3)
// [1, 2, 3]

Cygra

let foobar = (param1, param2 = "param2") => {
  console.log(param1);
  console.log(param2);
}

foobar(1);
// 1
// param2

Cygra

var FooBar = () => {};

console.log(FooBar.prototype);
// undefined

Cygra

let Clock = () => {
  this.sec = 0;

  setInterval(() => {
    this.sec ++;
  }, 1000)
}

var newClock = new Clock();

Cygra

"use strict";

function Clock() {
  var _this = this;

  this.sec = 0;
  setInterval(function () {
    _this.sec++;
  }, 1000);
}

Cygra

function Clock(){
  this.sec = 0;

  setInterval(() => {
    this.sec ++;
  }, 1000)
}

var newClock = new Clock();