flutter_sane_lints
flutter_sane_lints
flutter_sane_lints is a custom linting package for Dart and Flutter that helps developers write cleaner and more maintainable UI code. Its primary goal is to enforce best practices by flagging common issues directly in the IDE.
The Problem: Hardcoded Strings in UI
Hardcoding strings directly into your widget tree is a common practice that can lead to significant problems down the line, especially when it comes to app maintenance and internationalization (i18n). Every hardcoded string becomes a hurdle when you need to support multiple languages or update branding text across the app.
The Solution: A Custom Lint Rule
Inspired by native Android development, flutter_sane_lints introduces a new lint rule that raises a warning whenever it detects a hardcoded string literal within a widget. This encourages developers to externalize their strings from the beginning, leading to a more robust and scalable codebase.
Overview
A custom lint plugin to try and improve maintainability in Flutter projects by disallowing certain anti-patterns. At the moment, the only dart lint rule in this plugin is to avoid declaring ad-hoc strings inside Widget/State classes, or passing a literal to a Widget constructor.
Every String used for presentation (such as in a Text widget) should be defined in a l10n file. See Flutter Internationalization Tutorial.
Every String used for logic (such as in a switch statement) should be defined as an Enum or in any other way that makes sense for the use case while following good OO design. Using strings is a clear sign of primitive obsession and should be avoided.
Created with the Very Good CLI 💙
Installation 💻
❗ In order to start using Flutter Sane Lints you must have the Flutter SDK installed on your machine.
Add flutter_sane_lints and custom_lint to your pubspec.yaml:
dev_dependencies:
custom_lint:
flutter_sane_lints:
Install it:
flutter pub get
Usage 🚀
Add the custom_lint package to your analysis_options.yaml:
analyzer:
plugins:
- custom_lint
Available rules
At the moment this plugin contains only 2 rules:
- avoid_string_literals_inside_widget
This rule is equivalent to the Android's hard-coded string literals lint.
- avoid_if_with_enum
This rule is made to be used alongside the existing exhaustive_cases rule, as part of the default rules.
The existing Dart rule ensures you cover all enum cases in your switch statement, which is great for future-proofing your app. However, it does not raise a warning if you are using an if statement with your enum. This is bad, because using if with enum is the same as using a switch with default:
if (myValue == MyEnum.firstOption) {
doSomething();
}
is the same as
switch (myValue) {
case MyEnum.firstOption:
doSomething();
default:
// this default case violates exhaustive_cases
}
Therefore, using if statements with enum values violate Dart's rule of performing exhaustive switch.
Future work
More rules will be added in the future, but in the meantime, I am open to requests. Please go to the issues page and request for further features.
Learn More
I wrote a detailed article on Medium that walks through the process of creating this custom lint rule from scratch. You can read it here:
How to create a custom lint rule for Flutter
pub.dev
You can find the package on pub.dev: