feat: Adds custom equals for creating observables.

[amondnet]

Allows a reaction to be fired even if the value hasn't changed.
Adds custom equals for creating observables.

#844
fix #903

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Pull Request Checklist

• If the changes are being made to code, ensure the version in pubspec.yaml is updated.
• Increment the major/minor/patch/patch-count, depending on the complexity of change
• Add the necessary unit tests to ensure the coverage does not drop
• Update the Changelog to include all changes made in this PR, organized by version
• Run the melo run set_version command from the root directory
• Include the necessary reviewers for the PR
• Update the docs if there are any API changes or additions to functionality

[codecov]

Codecov Report

Merging #907 (c33a443) into master (ea1ba4f) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master     #907   +/-   ##
=======================================
  Coverage   98.98%   98.99%           
=======================================
  Files          56       56           
  Lines        1980     1987    +7     
=======================================
+ Hits         1960     1967    +7     
  Misses         20       20           

Flag	Coverage Δ
flutter_mobx	100.00% <ø> (ø)
mobx	98.55% <100.00%> (+<0.01%)	⬆️
mobx_codegen	100.00% <100.00%> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
mobx/lib/src/core.dart	100.00% <ø> (ø)
mobx/lib/src/api/annotations.dart	80.00% <100.00%> (+5.00%)	⬆️
mobx/lib/src/core/atom_extensions.dart	100.00% <100.00%> (ø)
mobx_codegen/lib/src/store_class_visitor.dart	100.00% <100.00%> (ø)
mobx_codegen/lib/src/template/observable.dart	100.00% <100.00%> (ø)

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[gabrielaraujoz]

Hey there @pavanpodila & @fzyzcjy is there any way of knowing when this pr will be reviewed/released? thanks a lot!

[fzyzcjy]

LGTM! Btw, I love https://pub.dev/packages/json_serializable's approach when it comes to defining a custom function. For example,

@JsonKey(fromJson: myMethod)
whatever_thing

Sth myMethod(Sth sth) { ... }

Then no need to provide a string

[Gaurav-CareMonitor]

Any updates on this?

[amondnet]

@fzyzcjy Yeah, I like the approach of json_serializable too. I've modified it as shown below.

bool customEquals(String? oldValue, String? newValue) => oldValue != newValue;

abstract class _TestStore with Store {
  _TestStore();

  @MakeObservable(equals: customEquals)
  String custom = 'stuff';

  @alwaysNotify
  String always = 'stuff';
}

[amondnet]

@all-contributors please add @fzyzcjy for review

[allcontributors]

@amondnet

I've put up a pull request to add @fzyzcjy! 🎉