Thread by @SandroMaglione

Error handling is hard, harder than you think 🤔

Let's just see a simple example 💁🏼‍♂️

In how many ways can this #dart code below fail?

The answer will surprise you 👇🧵

Note: fail can mean different things ☝️

Here we mean anything that will crash the app (if not handled)

Errors or Exceptions 👇

https://twitter.com/SandroMaglione/status/1581879229121122304

And the answer is... 🔟

Yes, 10 ways 🤯

Basically every function hides a potential issue

What? Well, let's see them all 👇

1️⃣ Uri.https

Yes, this can fail 🙄

Just take a look at its internal implementation: FormatException!

2️⃣ _httpClient.get

Well, that was easy 😅

Anything can fail in an http request, pay attention

3️⃣ statusCode != 200

Here we throw manually

Remember to check the status code, it may not always be obvious ☝️

4️⃣ jsonDecode

This needs the correct input format, otherwise 💥

5️⃣ as Map

Yes, 'as' can throw as well 😱

Check the thread below for more about this 👇

https://twitter.com/SandroMaglione/status/1581153528105472001

6️⃣ containsKey('results')

Here again we throw manually

We cannot do otherwise, we need the results 💁🏼‍♂️

7️⃣ as List

Again, 'as' is insidious 🐍

Check the docs for more details 📑

dart.dev/guides/languag…

8️⃣ isEmpty

If not results, then no data, then we throw 💁🏼‍♂️

9️⃣ as Map<String, dynamic>

'as' 🙄

https://twitter.com/SandroMaglione/status/1581153528105472001

🔟 Location.fromJson

fromJson hides an 'as' casting 👻

Well, if the data is invalid we cannot avoid throwing an Exception

Being aware of all the possible issues is the first step

Then it's all about making sure the app will not fail

And that's a whole new challenge 🙃

There are also other ways to handle errors in your app 🔜

Follow @SandroMaglione (me 👋) for more about #dart and #flutter