let name = "Alice";
(function() {
  let name = "Bob";
  console.log(name);
})();
console.log(name);

const sym1 = Symbol("id");
const sym2 = Symbol("id");
console.log(sym1 === sym2);

const name = "Alice";
const obj = {
  name: "Bob",
  getName() {
    return this.name;
  }
};

console.log(obj.getName.call({ name: "Charlie" }));

const arr = [1, 2, 3];
arr[10] = 11;
console.log(arr.length);

const obj = {
  a: 1,
  b: 2,
  a: 3
};
console.log(obj.a);

console.log([..."hello"]);

Number.prototype[Symbol.iterator] = function*() { yield *['a','b','c'] };
console.log([...1]);