feat: ionCheck and ionUncheck for ion-checkbox

[mahnuh]

Pull request checklist

Please check if your PR fulfills the following requirements:

• Tests for the changes have been added (for bug fixes / features)
• Docs have been reviewed and added / updated if needed (for bug fixes / features)
• Build (npm run build) was run locally and any changes were pushed
• Lint (npm run lint) has passed locally and any fixes were made for failures

Pull request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no api changes)
• Build related changes
• Documentation content changes
• Other (please describe):

What is the current behavior?

Issue Number: #19096

What is the new behavior?

• added ionCheck event to ion-checkbox which will be emitted when the checkbox is being checked
• added ionUncheck event to ion-checkbox which will be emitted when the checkbox is being unchecked

Does this introduce a breaking change?

• Yes
• No

Other information

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[brandyscarney]

Thank you for the PR! The checked property is provided in the detail of the ionChange event. Is there a reason you can't check for this?

const checkbox = document.querySelector('ion-checkbox');

checkbox.addEventListener('ionChange', (ev) => {
  console.log('Checked changed', ev.detail.checked);
});

Here's a Codepen example: https://codepen.io/brandyscarney/pen/ExYKaaX?editors=1011

[mahnuh]

Hey @brandyscarney,
sure, ionChange would work in most cases but as described in #19096 there are some cases where it doesn't. Basically when you want to determine if either the checked property changed because the user tapped on the checkbox or the model just changed. This is not possible with ionChange I guess, as it will be emitted in both cases?

[Gorgoroth]

@brandyscarney I agree, it makes sense to emit the checked and unchecked events. It's easy to do in this place, it's harder to handle the case of #19096 in business logic.

[mahnuh]

@brandyscarney just wondering if there are any updates on this?

[averyjohnston]

Thanks for the PR! We appreciate the work you've put in. In the time that's passed, we've slated some changes for the upcoming Ionic 7 release that will solve the problems this PR is targeting. Namely, the ionChange event is being modified to only fire for user-committed changes.

Here is the RFC for this change in general: #25532
And here is the PR for ion-checkbox in particular, which has already been merged into the v7.0 branch and will be available in the upcoming major release: #25923

As such, I'm going to go ahead and close this PR out. Thank you!