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Missing forwardRef in Query/ViewQuery should throw #4174
Description
Consider the following code
@Component({selector: 'accordion'})
@View({
template: `
<accordion-item></accordion-item>
<accordion-item></accordion-item>`,
directives : [forwardRef(() => AccordionItem)]
})
export class Accordion implements OnInit {
constructor(el: ElementRef, @ViewQuery(AccordionItem) items:QueryList<AccordionItem>) {
this.items = items;
}
onInit() {
console.log(this.items);
}
}
@Component({selector: 'accordion-item'})
@View({template: `...`})
export class AccordionItem {}This works, but items returns 0 results, which is wierd since there are two children (see plnkr below). The problem here is a missing forwardRef.
If you remove forwardRef from the directives property in Accordion you'll get this error message. Pretty useful.
Unexpected directive value 'undefined' on the View of component 'Accordion'
But if you miss forwardRef in @ViewQuery instead of an error you'll get 0 results, while it should throw a similar error to the above one.
See repro, switch between the constructors in Accordion class and you'll see that no errors are thrown but the length of the results changes.
PS: The title includes Query which I didn't test, but I'm assuming that both works similar.
Activity
jessegood commentedon Sep 14, 2015
Agreed. It would be nice if Angular told you when the type is
undefinedinside of@ViewQuery.Also, maybe in the future the TypeScript transpiler will add support for checking before use:
microsoft/TypeScript#4114
0x-r4bbit commentedon Sep 17, 2015
Just mentioning here that
@Queryand@ViewQueryare going away in favour of@ContentChildrenand@ViewChildrenvia #4237Your issue might remain tho.
ericmartinezr commentedon Oct 3, 2015
Closing it in favor of #4489
angular-automatic-lock-bot commentedon Sep 7, 2019
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