Consistent ionic NgModel components

[manucorporat]

We should revisit:

• checkbox
• date-time
• input
• text-area
• radio-group
• searchbar
• segment
• selector
• toggle

and events like (ionChange), (ionSelect) in across the framework: Tabs, SplitPane, SlidingItem...

Each one has a different policy when calling the callbacks.

• Some does not call onChange() when the value is changed from writeValue
• Some does fire the callbacks with the default value (others not)
• In general all these components are doing the same thing but from an implementation detail they are not consistent.

Examples:
Toggle: https://github.com/driftyco/ionic/blob/master/src/components/toggle/toggle.ts#L230-L246
Range: https://github.com/driftyco/ionic/blob/master/src/components/range/range.ts#L620-L649

I propose to create a new design document to describe how an ionic component should work through a base interface and a standarized behavior, we could even create "base unit tests" shared between all the inputs.

ping
@adamdbradley
@brandyscarney

I think this should be approached before ionic 2.0 final is released. Probably in 2.0rc2

[adamdbradley]

I started using abstract classes here for each of our input types, we can use this to come up with a standard. https://github.com/driftyco/ionic/blob/master/src/util/form.ts#L66

[manucorporat]

#9472

[manucorporat]

Ionic inputs should not break if userland code crashes. i.e. we should wrap calls to user's code with try{} catch

Pseudocode:

dispatchEvent() {
   try {
     this.userland();
   }catch() {
     // restore state and rethrow 
   }
}

[manucorporat]

#10532

[manucorporat]

All inputs to implement ionFocus and ionBlur
Related #10761

[manucorporat]

All events in ionic should behave the same:
(ionSelect), (ionChange), (ionInput)...

[manucorporat]

ng-valid handling inconsistency: #10952

[manucorporat]

#11005

[manucorporat]

#7806

[manucorporat]

#8935 (comment)

[ionitron-bot]

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