Chunky Monkey : Using Recursion

Tell us what’s happening:
Sorry to interrupt but I think you all can help me…I want to know how the recursion tree of this solution will form.
Because I want to understand how recursion is happening in this case…

Thanks if anyone can help…(:wink: sleeping:

Your code so far

   function chunkArrayInGroups(arr, size) {
      if (arr.length <= size){
        return [arr];
      else {
        return [arr.slice(0,size)].concat(chunkArrayInGroups(arr.slice(size),size));

chunkArrayInGroups(["a", "b", "c", "d"], 2);

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Link to the challenge:

Things in parentheses always go first, that’s what will allow recursion to happen

chunkArrayInGroups(["a", "b", "c", "d"], 2)

1° iteration -> skips the if and goes into else, returns [["a", "b"]].concat(chunkArrayInGroups(["c", "d"], 2))
2° iteration -> enters the if, returns [["c, "d"]]

Then it goes backwards:

2° iteration -> returned [["c", "d"]]
1° iteration -> second iteration value goes into our concat [["a", "b"]].concat([["c", "d"]]), which returns [["a", "b"], ["c", "d"]].

Not sure if I cleared the information or make it worse? This is actually a really good example of recursion, first you must make sure you understand exactly what slice and concat do, so you can worry only about the recursion. Second, every recursion must have an end condition, in our case is the if: if (arr.length <= size){. Third, imagine you are the compiler, go line by line thinking or writing exactly what the algorithm is doing.

1 Like

Thanks (:slight_smile: I like your explanation and understand the logic behind it…