Angular: NG0950: Input is required but no value is available yet (input.required / viewChild.required)

Meaning

input.required<T>() (and viewChild.required, contentChild.required) throw NG0950 / NG0951 if read before a value exists. Read them in ngOnInit or later, inside computed/effect, or in the template. In tests, set the input with fixture.componentRef.setInput(...) before the first detectChanges.

Common causes

• Reading this.name() in the constructor or a field initialiser that runs immediately
• Parent did not pass the required input (but the compiler is bypassed or the component is created dynamically)
• Test created the component without setting required inputs
• Reading a required view query before the view exists (NG0951)
• Dynamic component creation without setInput

Detailed fix by platform

Code examples

export class UserCardComponent {
  user = input.required<User>();
  title = computed(() => this.user().name);          // computed reads lazily: OK
  // constructor() { console.log(this.user()); }      // NG0950: nothing set yet
}
// test: fixture.componentRef.setInput('user', { name: 'Ada' }); fixture.detectChanges();

How to diagnose

1. Timing — Where is the input read?
2. Parent — Is the required input bound?
3. Test — setInput before detectChanges?

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