add error-handling exercise by A-O-Emmanuel · Pull Request #2732 · exercism/javascript

A-O-Emmanuel · 2025-07-24T23:44:23Z

Implemented the Error Handling practice exercise with solution, tests, and documentation

SleeplessByte · 2025-07-25T00:16:18Z

+    console.log = jest.fn();
+
+    try {
+      processString('');
+    } catch {
+      /*
+                intentionally left empty,
+                I expext this call to throw,
+                but only care about verifying that the finally block is executed
+                and clean up message logged.
+            */
+    }
+
+    expect(console.log).toHaveBeenCalledWith('Resource cleaned up');


I don't think this will work with the Browser Test Runner, but the idea is not wrong. I can help come up with an easy alternative to fix this.

okay, thank you

…m/A-O-Emmanuel/javascript into implement-error-handling-exercise

BNAndras

I’m not a track maintainer here, just a friendly maintainer from elsewhere on Exercism. I made some more general comments, but whatever SleeplessBytes and Cool-Kat say is the final word. :)

…r-handling.spec.js

SleeplessByte

What's there is almost done. The only issue I have is that this isn't actually handling any error!

SleeplessByte · 2025-08-19T21:41:40Z

@@ -0,0 +1,6 @@
+export const processString = (input) => {
+  //TODO: implement this


In all other stubs we throw new Error('...') (I don't recall the exact error message). We probably want to use that!

SleeplessByte · 2025-08-19T21:42:51Z

+    throw new TypeError();
+  }
+  if (input === '') {
+    throw new Error();


We almost always want a message in an error. We don't need to test the exact message, but throwing an empty error is non-idiomatic.

Alright, I'll add that

SleeplessByte · 2025-08-19T21:42:55Z

@@ -0,0 +1,9 @@
+export const processString = (input) => {
+  if (typeof input !== 'string') {
+    throw new TypeError();


We almost always want a message in an error. We don't need to test the exact message, but throwing an empty error is non-idiomatic.

Co-authored-by: Derk-Jan Karrenbeld <derk-jan+github@karrenbeld.info>

A-O-Emmanuel · 2025-08-26T20:35:04Z

Hi @SleeplessByte thanks for your review, sorry it took this long for me to reply, just to clarify, when you say "The only issue I have is that this isn't actually handling any error!" do you mean that the function should include descriptive error messages rather than handling more complex error scenarios?

SleeplessByte · 2025-08-28T14:58:18Z

@A-O-Emmanuel no worries! We are not in a hurry.

Right now, the exercise wants you to throw errors. It doesn't want you to handle the error.

Handling errors could be:

try { } catch { }

or

promise.catch(...)

or

try { } finally { }

or

promise.finally(...)

A-O-Emmanuel · 2025-08-28T15:51:29Z

Oh, that's true, I'll just have to revert back to the way I did it before. Thanks for the clarification, I've learnt something today, "throwing errors and handling errors" are two different things, yeah, it makes sense, thank you.

A-O-Emmanuel · 2025-12-28T00:45:25Z

hi @Cool-Katt I've made changes and added more tests, please review, and sorry for the delay.

A-O-Emmanuel · 2026-05-11T01:57:47Z

Hi @Cool-Katt have you been able to review the changes I made?

Cool-Katt · 2026-05-11T13:14:12Z

@A-O-Emmanuel Terribly sorry for the long delay! It shouldn't have taken me 5 months to rely, yikes 😬

I still stand by my previous suggestion, which is:
I don't like to just throw a generic Error because that way the tests will pass by default without having changed the code at all, so I propose instead to throw a RangeError for the two cases that test length and maybe a SyntaxError for the case with mixed letters/numbers. We don't have to test for a specific message, but we can test for a specific type of error and weather or not a message was included at all (which it should be).
Also, there should be a test that fails in case a generic Error is thrown.

Let me know if you still want to work on this?

A-O-Emmanuel · 2026-05-11T13:19:59Z

@Cool-Katt thanks for the comments, I will still work on it. by this weekend, I will create the commit with your suggestion, also, it's okay, I just thought you were busy. Thank you.

…est for generic errors and test for error messages

…m/A-O-Emmanuel/javascript into implement-error-handling-exercise Updating local branch

A-O-Emmanuel · 2026-05-16T19:07:47Z

@Cool-Katt I've just push the changes you requested, please review

A-O-Emmanuel · 2026-05-18T19:00:11Z

Hi @Cool-Katt @BNAndras @SleeplessByte @joshgoebel can anyone provide any feedback for this?

Cool-Katt

The PR for adding a new exercise should ideally only touch the files relevant to the new exercise being added, so please don't change any of the other files (even if it's just formatting, we have an auto formatter for this).

Also, see comments bellow

Cool-Katt · 2026-05-20T08:53:07Z

+      }
+
+      expect(error).toBeInstanceOf(Error);
+      expect(error.constructor).not.toBe(Error);


We only need this check of the three, but testing for a message is good in any case because we don't ant people to circumvent sending one.

Also, i feel like this should be the first test, followed by all the tests for the various error types and finally the two passing cases that test the functionality

Okay, thank you, and for the other files, sorry about that, It was mistake, I didn.t even know the formater ran for everyfile.

Cool-Katt · 2026-05-20T08:55:10Z

+        "uuid": "de1c75f2-2461-4347-b5ca-b3cfaafe4d79",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 1


set an appropriate difficulty level. You can cross reference on the site to see what level exercises show up al easy, medium or hard. (I don't remember the scale, sry)

Okay, I'll do this later today, thank you

Cool-Katt · 2026-05-20T09:05:36Z

@A-O-Emmanuel Overall good stuff. Just needs a few very minor tweaks and we can finally merge this

Co-authored-by: Cool-Katt <stani_s1@abv.bg>

A-O-Emmanuel · 2026-05-20T15:47:27Z

HI @Cool-Katt I've implemented the changes you request, please check if they are up to the standard you want, thank you

A-O-Emmanuel · 2026-05-21T13:53:06Z

okay, doing that now

Cool-Katt · 2026-05-21T13:55:06Z

@A-O-Emmanuel that was for the bot, but i got a typo. You don't have to do anything

Cool-Katt · 2026-05-21T13:55:13Z

/format

github-actions · 2026-05-21T13:55:25Z

The "Format code" action has started running.

github-actions · 2026-05-21T13:55:48Z

The "Format code" action has finished running.

github-actions · 2026-05-21T13:55:49Z

For security reasons, /format does not trigger CI builds when the PR has been submitted from a fork. If checks were not passing due to code format, trigger a build to make the required checks pass, through one of the following ways:

Push an empty commit to this branch: git commit --allow-empty -m "Trigger builds".
Close and reopen the PR.
Push a regular commit to this branch.

Cool-Katt

LGTM!

A-O-Emmanuel · 2026-05-21T14:10:36Z

Okay, thank you

A-O-Emmanuel · 2026-05-21T14:13:14Z

@Cool-Katt so it will be merged? or any other thing i need to do?

Cool-Katt · 2026-05-22T10:03:17Z

@A-O-Emmanuel Nothing else for you to do right now.

If @SleeplessByte approves as well (since they requested some changes) we can merge this.

A-O-Emmanuel · 2026-05-22T11:48:06Z

Okay, but I think @SleeplessByte was waiting for you to approve, let me send him a message

add error-handling exercise

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[CI] Format code

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SleeplessByte requested changes Jul 25, 2025

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Implement practice: error-handling #910

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A-O-Emmanuel added 2 commits July 29, 2025 01:27

add github username and update proof.ci.js and error-handling.js

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Merge branch 'implement-error-handling-exercise' of https://github.co…

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…m/A-O-Emmanuel/javascript into implement-error-handling-exercise

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Edit introduction and update proof.ci.js, error-handling.js, and erro…

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…r-handling.spec.js

A-O-Emmanuel requested a review from BNAndras August 2, 2025 23:16

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A-O-Emmanuel requested a review from SleeplessByte August 26, 2025 20:05

Update exercises/practice/error-handling/error-handling.js

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Co-authored-by: Derk-Jan Karrenbeld <derk-jan+github@karrenbeld.info>

A-O-Emmanuel and others added 3 commits September 23, 2025 01:02

edit introduction.md proof.ci.js and error-handling.js

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resolve merge conflict: kept local code

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Merge branch 'exercism:main' into implement-error-handling-exercise

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A-O-Emmanuel and others added 3 commits May 16, 2026 19:48

Merge branch 'exercism:main' into implement-error-handling-exercise

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Edit error-handling.spec.js to include test for specific errors and t…

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…est for generic errors and test for error messages

Merge branch 'implement-error-handling-exercise' of https://github.co…

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…m/A-O-Emmanuel/javascript into implement-error-handling-exercise Updating local branch

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Update exercises/practice/error-handling/.docs/introduction.md

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Co-authored-by: Cool-Katt <stani_s1@abv.bg>

Update exercises/practice/error-handling/.docs/introduction.md

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Update exercises/practice/error-handling/error-handling.spec.js

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Co-authored-by: Cool-Katt <stani_s1@abv.bg>

edit test file and change difficulty level to 4 which is medium

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[CI] Format code

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		@@ -0,0 +1,6 @@
		export const processString = (input) => {
		//TODO: implement this

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