Thread by @GonPalma

Using --dart-define, a 🧵

When we're developing Flutter apps we can have two issues:

1⃣ We want to add `flavors` for Flutter Web, but there's no out-of-the-box way of doing it

2⃣ Our app needs an API key or configuration that we don't want to commit

1/

In pure Dart, this can be easily achievable with the args package:

pub.dev/packages/args

We are able to stipulate what are the flags and arguments we need to use, such as:

`dart run bin/converter.dart --verbose --out-path="/out" data.json`

2/

This will:
1⃣ Run the converter.dart script
2⃣ With the flag verbose
3⃣ Setting an `out-path` of `/out`
4⃣ Accepting as a last argument the file `data.json`

However, the same cannot be applied to Flutter.

Why?

Because we have no direct control over

`flutter run`

3/

Thankfully Dart provides us a solution 🚀

Using --dart-define in our `flutter run` command we can specify a variable name and its value so that our Dart or Flutter application can use it 🙌

In this example, we define the "ENV" variable and set its value to "stg"

4/

Finally, we can use the `String.fromEnvironment` function to access our variable 🚀

With this we can specify:
🍭 Flavors for the web app
✍️ Misc configurations such as colors, name of the app or baseUrl
🔑 API keys to be injected in a CD step

5/

So now it's your turn! 😁

Have you used --dart-define before? 🤔

What did you use it for?

I'm very curious to know! 🙌