Angular · Theory

Control Flow

Theory

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Control Flow

Control Flow is a Angular topic. In plain words you use it for a Pass banner in a marks card. Don’t start with a slogan — start with that picture.

Smallest example: *ngIf="marks >= 40". Type it, run it, and say what you see. If you can do that from memory, you know Control Flow.

From the example next to this theory — Control Flow: toggle open.

Trap — *ngIf treating 0 as false. Fix that before you talk about advanced Angular.

Viva — what is Control Flow? Then show *ngIf="marks >= 40". Then name the trap.

Exam tip

What is Control Flow? Show this: *ngIf="marks >= 40". Trap: *ngIf treating 0 as false.

Example

import { Component } from "@angular/core";

@Component({
  selector: "app-root",
  template: `
    <h1>{{ title }}</h1>
    <button (click)="toggle()">Toggle</button>
    <p *ngIf="open">Panel open</p>
  `,
})
export class AppComponent {
  title = "Angular practice";
  open = true;
  toggle() {
    this.open = !this.open;
  }
}

Control Flow: toggle open. Say whether the panel is on screen after one click.

Short notes

DefControl Flow — a Pass banner in a marks card.
Rule*ngIf="marks >= 40"
Trap*ngIf treating 0 as false
Usea marks card

import { Component } from "@angular/core"; @Component({ selector: "app-root", template: ` <h1>{{ title }}</h1> <button (click)="toggle()">Toggle</button> <p *ngIf="open">Panel open</p> `, }) export class AppComponent { title = "Angular practice"; open = true; toggle() { this.open = !this.open; } }

Control Flow

Example

Short notes

Questions

Control Flow

Example

Short notes

Questions