console.log([1,2,3].findIndex(x => x === 2))
console.log([1,2,3].reverse())
console.log(typeof new Date())
console.log(typeof /abc/)
console.log(typeof Math)
console.log(typeof new Function())
console.log(typeof new Map())
console.log(typeof new Set())
console.log(typeof new WeakMap())
console.log(typeof new WeakSet())