Simple Primes

simple-primes.js

// ES5 :)
function isPrime (n) {
  for (i = 2; i < n; i++)
    if (n % i === 0) return false
  return true
}

// ES6 (readable)
isPrime = n => { for (i = 2; i < n; i++) if (n % i === 0) return false; return true }

// ES6 (Codegolfed to 55chars)
isPrime=n=>{for(i=2;i<n;i++)if(n%i==0)return false;return true}

// AssertGolf
assert=(c,t)=>{c?console.log(t):console.warn(t)}

// Tests
assert(isPrime(0)==1, "Zero is prime")
assert(isPrime(2)==1, "Two is prime")
assert(isPrime(3)==1, "Three is prime")
assert(isPrime(4)==0, "Four is not prime")
assert(isPrime(5)==1, "Five is prime")
assert(isPrime(6)==0, "Six is not prime")