Smallest Common Multiple (last two tests not passing)

Tell us what’s happening:

For some reason the last two tests are not passing. If I test this code somewhere else I get the right values for the last two tests.

Your code so far

function smallestCommons(arr) {
  let arr = arr.sort((a,b) => a - b);
  let arr2 = [];
  for(let i = arr[0]; i <= arr[arr.length -1]; i++)
  let x = true;
  let LCM = 0;
    for(let j=arr2[0]; j <= arr2[arr2.length -1]; j++)
      if(LCM % j !== 0)
      else if(j == arr2[arr2.length -1]) {
        x = false;

  return LCM;


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Link to the challenge:

This is a very common issue with that challenge. Your solution probably works but does not work efficiently enough so it sets off the infinite loop protection in free code camp

let arr = arr.sort((a,b) => a - b);

(arr is already declared as a parameter)

After that its the infinite loop protection error. You used to be able to disable it with //no-protect but now that doesn’t work.

let me guess, Dylan Israel?

He’s a nice FCC youtuber, i recommend you watch him.

Thanks, yes I got this solution from Dylan’s youtube channel. I was stuck on this challenge. I try to figure out most of them on my own or use the hints, but some of them have been extra challenging for me. I have been on the Intermediate Algorithms for a few weeks now :(. Literally right now just before I wrote this response I am staring blankly at the Steamroller challenge, not really sure where to start…after a bit of time I will probably come up with something usually that half works or works for 2 or 3 of the tests.

As for this solution, I know this isn’t the most efficient solution because with large numbers it can run very slow. Although I have been programming for awhile (mostly self taught and from my college courses but not work related) and I have a CIS degree, I find algorithms and coming up with the most efficient solutions to be extremely challenging. In my course work in college I did not practice these kinds of Algorithms (I guess because CIS isn’t Computer Science although I did programming and web development) I went straight to actually making useful things, but I get that these are the kinds of “white board” questions you get in interviews so I want to get better at it, so that’s why I am here.

I also used Dylan’s solution since i couldn’t figure it out either.

Practice make perfect. Don’t worry, i had a hard time also and then i slowly learned better and better ways.

We are glad to help here at FCC.

Dylan Israel’s solution had half as many lines of codes as mine. If he created that video cold, I’m quite impressed.

I built an isPrime function, a greatest common denominator function and returned an array.reduce value.

Seven more hops until the projects.