This diagnostics ensures that a standalone component which uses known control flow directives
(such as *ngIf
, *ngFor
, or *ngSwitch
) in a template, also imports those directives either
individually or by importing the CommonModule
.
import {Component} from '@angular/core';@Component({ // Template uses `*ngIf`, but no corresponding directive imported. imports: [], template: `<div *ngIf="visible">Hi</div>`,})class MyComponent {}
What's wrong with that?
Using a control flow directive without importing it will fail at runtime, as Angular attempts to bind to an ngIf
property of the HTML element, which does not exist.
What should I do instead?
Make sure that a corresponding control flow directive is imported.
A directive can be imported individually:
import {Component} from '@angular/core';import {NgIf} from '@angular/common';@Component({ imports: [NgIf], template: `<div *ngIf="visible">Hi</div>`,})class MyComponent {}
or you could import the entire CommonModule
, which contains all control flow directives:
import {Component} from '@angular/core';import {CommonModule} from '@angular/common';@Component({ imports: [CommonModule], template: `<div *ngIf="visible">Hi</div>`,})class MyComponent {}
Configuration requirements
strictTemplates
must be enabled for any extended diagnostic to emit.
missingControlFlowDirective
has no additional requirements beyond strictTemplates
.
What if I can't avoid this?
This diagnostic can be disabled by editing the project's tsconfig.json
file:
{ "angularCompilerOptions": { "extendedDiagnostics": { "checks": { "missingControlFlowDirective": "suppress" } } }}
See extended diagnostic configuration for more info.