Feature request: Enforce value of @Component.changeDetection

[philipbulley]

In the project I'm currently working on, it'd be useful to ensure that all components are set to use changeDetection: ChangeDetectionStrategy.OnPush.

[mgechev]

Sounds good, I'm only afraid it could be misleading for components which produce/rely on side-effects.

I'm not sure there's a good way to predict if a component is suitable for OnPush ChangeDetectionStrategy. Do you have any ideas?

[mgechev]

Let's close it since it's very hard to guess if a component produces a side-effect &/|| depends on global state or not.

[guojenman]

@mgechev How about enforcing the existence of changeDetection? At least this way, it's a conscious decision by the developer to say whether it is or not. This would prevent accidental default change detection by an accidental omission.

@mgechev A rule for this is landing soon in material2, would be nice to include this rule in codelyzer. It uses a whitelist to disable it for certain components.
angular/components#5707

[mgechev]

Okay, lets reopen the issue.

An even more beautiful rule has landed in material2, to lint any property value of any decorator:
https://github.com/angular/material2/blob/master/tools/tslint-rules/validateDecoratorsRule.ts

[itsdevdom]

In our case, we're developing an Angular component library in which every component must have set the change detection strategy to OnPush. We also try to build our applications using OnPush everywhere.

Thus, it would be awesome to have linting rule for that!

[mgechev]

Okay, lets do that. Maybe as argument of the rule we can provide a regex for matching the components which should have OnPush. By default it can be .*.

[amcdnl]

Whats the status on this? Would love to incorporate this.

[wKoza]

I think that you can do it. If we want to bypass this rule, we can also simply mark our component with tslint:disable:onPushStrategy(with a comment)