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.