NaN (Not a Number).

1. Why does not NaN equal(==) or strict equal(===) to NaN itself?
2. How we can evaluate the following conditions to true?

let x = NaN;
// equal(==)
if(x == NaN) {
    console.log(`${x} (Not a Number)`);
}
// strict equal(===)
if(x === NaN) {
    console.log(`${x} (Not a Number)`);
}