// Unique array
const arr = [1, 1, 2, 3, 4, 4, 5];
const uniqueArr = [...new Set(arr)];

// Convert string to number
const str = '22';
const num = +str;
const num2 = ~~str

// Convert to boolean
const isTrue  = !0;
const isFalse = !1;
const alsoFalse = !!0;

// Exponentiation
const n = 8;
const pow = 2 ** n;

// Remove all elements from array except n first
const arr = [1, 2, 3, 4, 5];
const n = 2;
arr.length = n;