square.js

// A square of squares

// You like building blocks. You especially like building blocks that are squares. And what you even like more, is to arrange them into a square of square building blocks!

// However, sometimes, you can't arrange them into a square. Instead, you end up with an ordinary rectangle! Those blasted things! If you just had a way to know, whether you're currently working in vain… Wait! That's it! You just have to check if your number of building blocks is a perfect square.
// Task

// Given an integral number, determine if it's a square number:

//     In mathematics, a square number or perfect square is an integer that is the square of an integer; in other words, it is the product of some integer with itself.

// The tests will always use some integral number, so don't worry about that in dynamic typed languages.
// Examples

// -1  =>  false
//  0  =>  true
//  3  =>  false
//  4  =>  true
// 25  =>  true
// 26  =>  false

var isSquare = function(n){
  return n >= 0 && Math.sqrt(n) % 1 === 0;
}