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Angular Property binding best practices example code

Here are some best practices for using property binding in Angular:

1. Use the [property] syntax for property binding: Instead of using the bind-property syntax, use the [property] syntax for property binding. This makes the binding more readable and consistent with other Angular syntax.

2. Use ngIf and ngFor directives to conditionally render elements: Instead of using property binding to conditionally show or hide elements, use the ngIf and ngFor directives. These directives are specifically designed for this purpose and can improve the performance of the application.


Error: {{errorMessage}}


Error: {{errorMessage}}

3. Use one-way binding for read-only properties: Use one-way binding ([property]) for read-only properties and two-way binding ([(ngModel)]) for properties that need to be updated from the template.

4. Use the async pipe for observables: Instead of manually subscribing to observables in the component and updating the view, use the async pipe. The async pipe subscribes to an observable and updates the view automatically.



  {{user.name}}




  {{user.name}}

5. Use property binding with care: Property binding can be useful, but it can also make the code less readable, harder to debug and cause performance issues.

It’s worth noting that using property binding excessively can lead to tight coupling between the component and the template, which can make it harder to test and maintain the component.

It’s recommended to use property binding judiciously and use other Angular features such as directives, services, and the component lifecycle hooks to manage the component’s state and behavior.

Angular Avoid side effects example code

Here’s an example of how to avoid side effects in an Angular component:

1. Isolate component logic: Instead of directly manipulating the DOM or other components, use the component’s input and output properties to communicate with other parts of the application. This makes the component more isolated and easier to test.

// Good
@Input() user: User;

// Bad
@ViewChild('usernameInput') input: ElementRef;

2. Avoid changing input properties: Input properties should be treated as immutable. Avoid changing the values of input properties within the component. This can cause unexpected behavior and make the component harder to reason about.

// Good
sortUsers(users: User[]) {
  return users.sort((a, b) => a.name.localeCompare(b.name));
}

// Bad
@Input() users: User[];

sortUsers() {
  this.users.sort((a, b) => a.name.localeCompare(b.name));
}

3. Avoid subscriptions in the constructor: It’s a best practice to avoid subscribing to observables in the constructor. Instead, use the ngOnInit lifecycle hook and make sure to unsubscribe in the ngOnDestroy lifecycle hook.

// Good
export class ExampleComponent implements OnInit, OnDestroy {

Angular Return the proper type example code

Here’s an example of how to return the proper type in an Angular service:

1. Use a strongly-typed return type: Use a strongly-typed return type for the service’s methods to ensure that the correct type is returned.

import { Injectable } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { Observable } from 'rxjs';
import { User } from './user';

@Injectable({
  providedIn: 'root'
})
export class UserService {
  constructor(private http: HttpClient) {}

  getUser(): Observable {
    return this.http.get('/api/user');
  }
}

In this example, the getUser method has a return type of Observable, which ensures that the method returns an observable of the User type.

2. Use Typescript’s type inference: If the return type can be inferred from the implementation, Typescript will automatically infer the return type and you don’t have to explicitly specify it.

@Injectable({
  providedIn: 'root'
})
export class UserService {
  constructor(private http: HttpClient) {}

  getUser() {
    return this.http.get('/api/user');
  }
}

In this case, the return type of getUser method is Observable inferred by the type of the http.get request

3. Use the as keyword: If you want to cast the return value to a specific type, use the as keyword.

@Injectable({
  provided

Angular Property binding best practices – Passing in a string example

Here’s an example of how to use property binding best practices when passing in a string:

1. Use one-way binding for read-only properties: When passing in a string as a property value, use one-way binding ([property]) if the value is read-only.

2. Use string literals instead of variables: When passing in a string as a property value, it’s best to use string literals instead of variables. This makes the binding more readable and eliminates the need for unnecessary component state.

3. Avoid complex expressions or function calls: When passing in a string as a property value, avoid using complex expressions or function calls. This can make the binding less readable and harder to debug.

4. Use property binding with care: Property binding can be useful, but it can also make the code less readable, harder to debug and cause performance issues. Therefore, it’s recommended to use property binding judiciously, and use other Angular features such as directives, services, and the component lifecycle hooks to manage the component’s state and behavior.

Angular Property binding best practices – Passing in an object example code

Here’s an example of how to use property binding best practices when passing in an object:

1. Use one-way binding for read-only properties: When passing in an object as a property value, use one-way binding ([property]) if the value is read-only.

2. Use object literals instead of variables: When passing in an object as a property value, it’s best to use object literals instead of variables. This makes the binding more readable and eliminates the need for unnecessary component state.

3. Avoid complex expressions or function calls: When passing in an object as a property value, avoid using complex expressions or function calls. This can make the binding less readable and harder to debug.

It’s also worth noting that, when passing complex objects as properties, it’s important to ensure that the objects are immutable, to avoid unexpected behavior and make the component easier to reason about.