Find the longest word using recursion

[lionzebrowski]

Hey guys, could someone explain to me what’s happening in the recursive call in this function?

function findLongestWordLength(str) {
  var words = str.split(" ");
 /* BASE CALL*/
  if (words.length === 1) {
    return words[0].length;
  }
/* RECURSIVE CALL*/
  return Math.max(
    words[0].length,
    findLongestWordLength(words.slice(1).join(" ")) //Why don't we use .length here? 
  );
}

console.log(
  findLongestWordLength("The quick brown fox jumped over the lazy dog")
  );

[bbsmooth]

@lionzebrowski

words.slice(1).join(” ")

findLongestWordLength takes a string argument, so if you are going to call it recursively then you need to pass it a string. What does the above code return? Why would we need the length property here?

P.S. Using recursion to solve this problem is probably not the best method as it adds unneeded complexity to what is really a very simple solution.

[shugyoza]

It’s probably better for you to pseudocode the function (i.e., writing the plain english sentence for each line of the function), e.g.:

function findLongestWordLength(str) {
  var words = str.split(" ");  // convert the sentence into an array of words
  if (words.length === 1) {  // ...
...
}

Search in google or Mozilla Developer Network for any operation that you don’t know, e.g.: what is .join javascript? what is .split? .slice method javascript?
Reverse engineering is one of the best way to learn. If you can do this, next time you have a difficult problem, you can pseudocode first before diving into writing the function. Beside, pseudocoding a perfectly working function could help nail that understanding in our head more solid.

[lionzebrowski]

Thank you sir. I was stuck with this for hours and now it makes sense! Yes, I agree. I was just looking at more complex solutions to these basic algorithm challenges here on freeCodeCamp, just to challenge myself you know.

[lionzebrowski]

That’s right sir, I try to do that as much as possible. It’s really helpful!

I already know the .slice() and .join() methods on JavaScript. I was just curious with the function code in the recursive call, as it was difficult to understand. @bbsmooth already said that the str argument has to be a string in order to execute the recursive call.

[ilenia]

I’ve edited your post for readability. When you enter a code block into a forum post, please precede it with a separate line of three backticks and follow it with a separate line of three backticks to make it easier to read.

You can also use the “preformatted text” tool in the editor (</>) to add backticks around text.

See this post to find the backtick on your keyboard.
Note: Backticks (`) are not single quotes (’).

[lionzebrowski]

No problem. This is my first time asking for a solution here on the forum, I didn’t know I was supposed to do that.

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