Enforcing Strict Templates in Angular Components

Angular's template syntax provides powerful features for building dynamic user interfaces. However, without proper enforcement, developers might accidentally introduce template errors that are only caught at runtime, leading to unexpected behavior and debugging difficulties. This challenge focuses on leveraging Angular's built-in capabilities to create components with strictly enforced template syntax, ensuring type safety and catching potential errors during development.

Problem Description

Your task is to create an Angular component that utilizes strict template checking. This means that the component's template should be analyzed by the Angular compiler for type errors, unbound variables, and other potential issues before the application is run. You will need to:

1. Create a new Angular component.
2. Implement a simple component logic that involves component properties and template bindings.
3. Configure your Angular project for strict template checking. (This is a project-level configuration, but your component will be the test case.)
4. Demonstrate how strict templates catch an error by intentionally introducing a common templating mistake in your component.

Key Requirements:

• The component must have at least one public property.
• The component's template must bind to this public property using interpolation or property binding.
• You must be able to identify the project-level configuration that enables strict templates.
• You must intentionally introduce a template error that would be caught by strict templates.

Expected Behavior:

When running ng build or ng serve with strict templates enabled, the Angular compiler should flag the intentional template error. The build or serve process should fail or warn prominently, indicating the presence of the error.

Edge Cases:

• Consider how strict templates interact with optional properties or properties that might be undefined initially.

Examples

Example 1:

• Component Logic:

  // my-strict.component.ts
  import { Component } from '@angular/core';
  
  @Component({
    selector: 'app-my-strict',
    templateUrl: './my-strict.component.html',
  })
  export class MyStrictComponent {
    userName: string = 'Alice';
  }
  

• Template (Correct):

  <!-- my-strict.component.html -->
  <p>Welcome, {{ userName }}!</p>
  

• Project Configuration (Conceptual): angular.json or tsconfig.json needs to have strictTemplates enabled.
• Output (During ng build / ng serve): No errors related to template syntax.

Example 2:

• Component Logic:

  // my-strict.component.ts
  import { Component } from '@angular/core';
  
  @Component({
    selector: 'app-my-strict',
    templateUrl: './my-strict.component.html',
  })
  export class MyStrictComponent {
    userAge: number = 30;
  }
  

• Template (Intentional Error):

  <!-- my-strict.component.html -->
  <p>Your age is {{ userAeg }}</p> <!-- Typo: 'userAeg' instead of 'userAge' -->
  

• Project Configuration (Conceptual): strictTemplates is enabled.
• Output (During ng build / ng serve): The Angular compiler will report an error similar to: Error: Can't bind to 'userAeg' since it isn't a known property of 'p'. or Property 'userAeg' is not defined on class MyStrictComponent. (The exact wording may vary slightly based on Angular version). The build process will fail.

Constraints

• The Angular project must be a recent version (e.g., Angular 10 or later, where strictTemplates is widely supported and encouraged).
• You must use the Angular CLI for project setup and building.
• The solution should be presented as a functional Angular component with its corresponding template file.
• The focus is on demonstrating the concept of strict template checking, not on complex component interactions or advanced Angular features.

Notes

• Enabling strictTemplates is a project-level configuration, typically found in angular.json within the build.options or globally in tsconfig.json for the application's TypeScript configuration.
• Strict templates help catch errors like typos in property names, accessing properties that don't exist on the component class, or using incorrect data types in bindings.
• The specific error message might differ slightly depending on the Angular version, but the core principle of compiler-detected errors remains the same. Your goal is to show that the error is detected.