coffeescript prime number generation - coffeescript

Question

I am trying to generate prime numbers like this:
generatePrimeNumbersBelowN = (n) ->
for i in [2..n-1]
isPrime = true
for j in [2..i-1]
isPrime = false if i % j == 0
break if not isPrime
console.log(i, "is Prime Number.") if isPrime
generatePrimeNumbersBelowN(100);
I am getting prime numbers from 3 to 97, inclusive. I am new to JavaScript/CoffeeScript, so please tell me what's happening to 2?
Here's the generated JS code:
var generatePrimeNumbersBelowN;
generatePrimeNumbersBelowN = function(n) {
var i, isPrime, j, k, l, ref, ref1, results;
results = [];
for (i = k = 2, ref = n - 1; 2 <= ref ? k <= ref : k >= ref; i = 2 <= ref ? ++k : --k) {
isPrime = true;
for (j = l = 2, ref1 = i - 1; 2 <= ref1 ? l <= ref1 : l >= ref1; j = 2 <= ref1 ? ++l : --l) {
if (i % j === 0) {
isPrime = false;
}
if (!isPrime) {
break;
}
}
if (isPrime) {
results.push(console.log(i, "is Prime Number."));
} else {
results.push(void 0);
}
}
return results;
};
generatePrimeNumbersBelowN(100);

Answer 1

generatePrimeNumbersBelowN = (n) ->
for i in [2..n-1]
isPrime = true
for j in [2..i-1]
isPrime = false if i % j == 0
break if not isPrime
console.log(i, "is Prime Number.") if isPrime
When i is 2, j ranges from 2 down to 1. You then check i % j which is 2 % 1 which is zero and claim that 2 is not a prime.
Because for x in [b..a] delivers a downward loop from b to a, while loop construct solves this problem.
generatePrimeNumbersBelowN = (n) ->
i = 2
while i < n
isPrime = true
j = 2
while j < i
isPrime = false if i % j == 0
break if not isPrime
j++
console.log(i, "is Prime Number.") if isPrime
i++
generatePrimeNumbersBelowN(100);