Collatz.js

/*
Description:
Preface
A collatz sequence, starting with a positive integern, is found by repeatedly applying the following function to n until n == 1 :

collatz sequence
 n = { n / 2 for even n ;
      3n + 1 for odd n }
=======

A more detailed description of the collatz conjecture may be found on Wikipedia.

The Problem
Create a function collatz that returns a collatz sequence string starting with the positive integer argument passed into the function, in the following form:

"X0->X1->...->XN"

Where Xi is each iteration of the sequence and N is the length of the sequence.

Sample Input
collatz(4); // should return "4->2->1"
collatz(3); // should return "3->10->5->16->8->4->2->1"
Don't worry about invalid input. Arguments passed into the function are guaranteed to be valid integers >= 1.
*/
function collatz(n){
  let num=[];
  for (let i=n;;){
    if (i===1){
    num.push(i)
    break
    }
    if (i%2===0) {
    num.push(i)
    i=i/2
    } else {
    num.push(i)
    i=i*3+1
    }
  }
  return num.join('->')
}