javascript

const a = {};
const b = { key: "b" };
const c = { key: "c" };

a[b] = 123;
a[c] = 456;

console.log(a[b]);

let x = 10;
let y = (x++, x + 5);

console.log(x, y);

console.log(typeof NaN);
console.log(NaN === NaN);

let a = "5";
let b = 2;
let result = a - b + b;

console.log(result);

let a = [1, 2, 3];
let b = a;
a = [4, 5, 6];

console.log(b);

let a = 0;

if (a = 5) {
  console.log("True");
} else {
  console.log("False");
}

function test() {
  var a = 5;
  return function () {
    console.log(a);
    var a = 10;
  };
}
test()();