Achieving a number pattern like 1, 2, 3, 1, 2, 3 in JavaScript

Question

I have been trying to create a function that would result in a repeated set of numbers if used in a for loop. If I’m using numbers 1–5, I should see a pattern of 1, 2, 3, 4, 5, 1, 2, 3, 4, 5 in the console.

To do this, I start by finding the remainder of dividing the current interval by the greatest number in the set (5). For example:

1 % 5 gives me 1,
2 % 5 = 2,
3 % 5 = 3,
4 % 5 = 4,
5 % 5 = 0,
and 6 % 5 should give me 1 again.

Here is the function I used:

function patternItem(x, lastNum) {
  return (x % lastNum);
}

console.clear();
for (var i = 1; i <= 10; ++i) {
  console.log(patternItem(i, 5));
}

I am trying to do this without having to force 5 for every remainder of 0. In other words, I want to avoid writing the function like this or similar:

function patternItem(x, lastNum) {
  let rem = x % lastNum;
  return rem != 0 ? rem : lastNum;
}

So far, I haven’t had any luck. What sort of complex formula would I need for the function?

Answer 1

With slight variation in your code

1. Change initial value of i to 0 and condition to < instead of <=.
2. Update the function return statement to return x % lastNum + 1 for returning 1 while reminder is 0.

---

function patternItem(x, lastNum) {
  return x % lastNum + 1;
}

console.clear();
for (var i = 0; i < 10; ++i) {
  console.log(patternItem(i, 5));
}

Answer 2

Just start at 0 and add 1:

function patternItem(x, lastNum) {
  return x % lastNum;
}
for (var i = 0; i < 10; ++i) {
  console.log(patternItem(i, 5) + 1);
}