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Who's afraid of recursion?

 ·   ·  ☕ 2 min read

Spoiler alert: I am.

What is recursion anyway?

A program calling itself.

How does it look?

conquerPlanet() {
  // infinite loop - there are too many planets to conquer

OK.. how about a practical use case?

Well, I am not quite a ‘theory’ guy. But here you go with the age old problem of calculating factorial.

function getFacty(num) {
  if (num > 0) return num * getFacty(num - 1);
  else return 1;

const result = getFacty(10);
console.log("result", result);

Why use recursion?

The program looks elegant, doesn’t it?

Recursion is also said to be better at “tree traversal”, a fancy term that represents the internal processing to get to the right data in a repeating task.

Why not use recursion?

The program just looked fine with our friend, the ‘for’ loop.

const num = 10;
let result = 1;
for (let i = num; i > 1; i-- ){
  result = result * i;
console.log("result-likey", result);

Or, rewrite using the other 10000 loop types at your disposal.

My opinion of why not to use recursion -

  • It is said to be more memory intensive (new stack / instance getting created for each call)
  • More CPU
  • I just don’t like it (I carry this opinion based on ‘nothing’. Ah, the bane of being a stupid programmer)

Help, why is this post going on for more than 10 lines..

Or, conclusion
You can be alive without recursion for sure. But be fair - the recursion looks elegant.

Aside: Did you know that you can execute the Javascript scripts (?) outlined above either by putting them in a simple ‘facty.js’ file and executing the file using ‘node’? Or you can say “eff it” and use an online playground like JSComplete?

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Prashanth Krishnamurthy
Prashanth Krishnamurthy
Technologist | Creator of Things