Angular: Make CLI templates compatible with TS strict mode #12081
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More and more devs are using TS strict mode as it's advocated by TS team. So generate Angular with strict mode activated.
gaetanmaisse
requested review from
igor-dv,
ndelangen,
shilman and
stijnkoopal
as code owners
| @@ -37,7 +37,7 @@ export default class ButtonComponent { | |||
| * @required | |||
| */ | |||
| @Input() | |||
| label: string; | |||
| label = 'Button'; | |||
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Why can't this just be a required string? I don't know if it makes sense to have a default value?
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@shilman you mean optional? I was going to make it optional but the @required 2 lines above and it scared me 😱 😄 .
If we want to keep it as "string" we need to provide a default value, otherwise, it's a string | undefined
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Why can't it be required and NOT have a default value?
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Because of strictPropertyInitialization (enabled in strict mode): https://devblogs.microsoft.com/typescript/announcing-typescript-2-7/#stricter-class-property-checks
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Well, this actually makes sense. The Angular compiler does not force you to set required Inputs in your template. Thus, even if you claim that an Input is required, at runtime it might be undefined if you don't assign a default value.
On the other hand, even if the Angular compiler enforced this, how would the framework-agnostic Typescript compiler know this?
So, this problem arises from the way of how components are built upon Typescript classes.
Issue: #12070
What I did
How to test