有没有一种简单的方法可以在 Flutter 中尽可能多地添加 Const？

Question

I have read the article here about Final and Const . I also saw many example code from flutter team use many const as they can (just read the example of todos list from package river_pod), and some article about how compile-time constant widget good for performance ( like this ).

Is there any easy way let the IDE plugin/lint add const Widget/Variable as much as it can automatically? Or give some hint like This Widget/Variable' is better to use with const .

I checked the lint package here and read Effective Dart:Style , but didn't see any information about it.

Thanks for help!

I add some example cases:

ListView(
  padding: const EdgeInsets.symmetric(horizontal: 20, vertical: 40), // here
  children: [ ...
    const SizedBox(height: 42), //here
    const Image( //here
      width: 100,
      height: 100,
      image: AssetImage('assets/logo.png'),
    )
    ...

or even a class

Container(
  child: const Toolbar(), //here
...

class Toolbar extends HookWidget {
  const Toolbar({Key key}) : super(key: key); //here
  ...

Answer 1

It's actually quite simple. You should open analysis_options.yaml and then under linter specify the required rules.

...
linter:
  rules:      
    - prefer_const_declarations

You can check the rules here: https://dart-lang.github.io/linter/lints/index.html

Answer 2

In addition to linting, you can fix most cases of missing or redundant const automatically by running dart fix --apply<\/code> . Run dart fix --dry-run<\/code> first to see what will change.

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