Skip to main content

Angular 9 Coding Style Guideline - 8, 7, 6, 5, 4, 2

The Angular coding guideline will helps us to understand to write the great code. It must be follows each and every Angular developers.

Explore -  What Are Differences in Angular 9, 8, 7, 6, 5, 4, 2?

Single Responsibility -
Apply the single responsibility principle (SRP) to all components, services, and other symbols. This helps make the app cleaner, easier to read and maintain, and more testable.

Rule of One - Do define one thing, such as a service or component, per file and consider limiting files to 400 lines of code.

Small functions - Do define small functions and consider limiting to no more than 75 lines.
General Naming Guidelines -
Do use consistent names for all symbols and the recommended pattern is - feature.type.ts.

Separate file names with dots and dashes -
1.      Do use dashes to separate words in the descriptive name.
2.      Do use dots to separate the descriptive name from the type.
3.      Do use consistent type names for all components following a pattern that describes the component's feature then its type. A recommended pattern is feature.type.ts.
4.      Do use conventional type names including .service, .component, .pipe, .module, and .directive. Invent additional type names if you must but take care not to create too many.
Example - users.service.ts | users.pipe.ts |users.module.ts
Note - don't user short form like - srv, .svc, .srve. It is very confusing.

Symbols and file names -
1.      Do use consistent names for all assets named after what they represent.
2.      Do use upper camel case for class names.
3.      Do match the name of the symbol to the name of the file.
4.      Do append the symbol name with the conventional suffix (such as Component, Directive, Module, Pipe, or Service) for a thing of that type.
5.      Do give the filename the conventional suffix (such as .component.ts, .directive.ts, .module.ts, .pipe.ts, or .service.ts) for a file of that type.

Symbol Name, do like this - 
@Component({ ... })
export class UsersComponent { }

OR   

@Component({ ... })
export class UserDetailComponent { }

OR

@Pipe({ name: 'initCaps' })
export class InitCapsPipe implements PipeTransform { }

OR

@Injectable()
export class UserProfileService { }

File Name, do like this -
users.component.ts

OR

user-detail.component.ts

OR

init-caps.pipe.ts

OR

user-profile.service.ts

Bootstrapping -
1.      Do put bootstrapping and platform logic for the app in a file named main.ts.
2.      Do include error handling in the bootstrapping logic.
3.      Avoid putting app logic in main.ts. Instead, consider placing it in a component or service.
Example -

import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';
import { AppModule }              from './app/app.module';
platformBrowserDynamic().bootstrapModule(AppModule)
  .then(success => console.log(`Bootstrap success`))
  .catch(err => console.error(err));

Component Selectors -
Do use dashed-case or kebab-case for naming the element selectors of components.
Example - The prefix toh represents Tour of Users

Do like this -
@Component({
  selector: 'toh-user-button',
  templateUrl: './user-button.component.html'
})
export class UserButtonComponent {}

Avoid using like this -
@Component({
  selector: 'tohuserButton',
  templateUrl: './user-button.component.html'
})
export class UserButtonComponent {}

Component custom prefix -
1.      Do use a hyphenated, lowercase element selector value; for example, admin-users.
2.      Do use a custom prefix for a component selector.
3.      Do use a prefix that identifies the feature area or the app itself.

Example - Do like this,
@Component({
  selector: 'admin-users'
})
export class UsersComponent {}

And avoid like this,
// UsersComponent is in an Admin feature
@Component({
  selector: 'users'
})
export class UsersComponent {}

Directive custom prefix -
1.      Do use a custom prefix for the selector of directives (e.g, the prefix toh from Tour of Users).
2.      Do spell non-element selectors in lower camel case unless the selector is meant to match a native HTML attribute.

Example, Do like this,
/* Do this */
@Directive({
  selector: '[tohValidate]'
})
export class ValidateDirective {}

And avoid like this,
/* avoid */
@Directive({
  selector: '[validate]'
})
export class ValidateDirective {}

Pipe names -
Do use consistent names for all pipes, named after their feature. The pipe class name should use UpperCamelCase and the corresponding name string should use lowerCamelCase. The name string cannot use hyphens ("dash-case" or "kebab-case")

Symbol Name -
@Pipe({ name: 'ellipsis' })
export class EllipsisPipe implements PipeTransform { }

OR  
@Pipe({ name: 'initCaps' })
export class InitCapsPipe implements PipeTransform { }

File Name -
ellipsis.pipe.ts

OR

init-caps.pipe.ts

Unit test file names -
1.      Do name test specifications file the same as the component they test.
2.      Do name test specification files with a suffix of .spec.

For example,
Components/ users.component.spec.ts/ user-detail.component.spec.ts
Services/  user.service.spec.ts/ logger.service.spec.ts
Pipes/  ellipsis.pipe.spec.ts/ init-caps.pipe.spec.ts

End-to-End (E2E) test file names -
Do name end-to-end test specification files after the feature they test with a suffix of .e2e-spec.

Example,
End-to-End Tests/  app.e2e-spec.ts/ users.e2e-spec.ts

Angular NgModule names -
Do append the symbol name with the suffix Module.
Do give the file name the .module.ts extension.
Do name the module after the feature and folder it resides in.

Examples,

Symbol Name -    
@NgModule({ ... })
export class AppModule { }

OR

@NgModule({ ... })
export class HeroesModule { }

OR

@NgModule({ ... })
export class AppRoutingModule { }

File Name -
app.module.ts

OR
users.module.ts

OR
app-routing.module.ts

By Anil Singh | Rating of this article (*****)

Popular posts from this blog

39 Best Object Oriented JavaScript Interview Questions and Answers

Most Popular 37 Key Questions for JavaScript Interviews. What is Object in JavaScript? What is the Prototype object in JavaScript and how it is used? What is "this"? What is its value? Explain why "self" is needed instead of "this". What is a Closure and why are they so useful to us? Explain how to write class methods vs. instance methods. Can you explain the difference between == and ===? Can you explain the difference between call and apply? Explain why Asynchronous code is important in JavaScript? Can you please tell me a story about JavaScript performance problems? Tell me your JavaScript Naming Convention? How do you define a class and its constructor? What is Hoisted in JavaScript? What is function overloadin

Angular 2, 4, 5, 6, 7, 8 and 9 Interview Questions and Answers -Books

» Are you preparing for Angular Interview? Buy this book (Including Angular 8, 7, 6, 5,4, 2) Interview Q/A Interview Q/A Interview Q/A Interview Q/A Interview Q/A Interview Q/A Interview Q/A » A Complete Guide Book of Angular 9 This is a concise, complete overview of the key aspects of Angular 9. It is fully up to date with the latest release of Angular. This article provide all the important aspects required for angular developers looking for brief and useful content... Posted In Angular 9 » A Complete Guide Book of Angular 8 This is a concise, complete overview of the key aspects of Angular 9. It is fully up to date with the latest release of Angular. This article provide all the important aspects required for angular developers looking for brief and useful content... Posted In Angular 8 » A Complete Guide Book of Angular 7 This is a concise, complete overview of the key aspects of Angular 7. It is fully up to date with the latest release of Angular. This

25 Best Vue.js 2 Interview Questions and Answers

What Is Vue.js? The Vue.js is a progressive JavaScript framework and used to building the interactive user interfaces and also it’s focused on the view layer only (front end). The Vue.js is easy to integrate with other libraries and others existing projects. Vue.js is very popular for Single Page Applications developments. The Vue.js is lighter, smaller in size and so faster. It also supports the MVVM ( Model-View-ViewModel ) pattern. The Vue.js is supporting to multiple Components and libraries like - ü   Tables and data grids ü   Notifications ü   Loader ü   Calendar ü   Display time, date and age ü   Progress Bar ü   Tooltip ü   Overlay ü   Icons ü   Menu ü   Charts ü   Map ü   Pdf viewer ü   And so on The Vue.js was developed by “ Evan You ”, an Ex Google software engineer. The latest version is Vue.js 2. The Vue.js 2 is very similar to Angular because Evan You was inspired by Angular and the Vue.js 2 components looks like -

nullinjectorerror no provider for httpclient angular 17

In Angular 17 where the standalone true option is set by default, the app.config.ts file is generated in src/app/ and provideHttpClient(). We can be added to the list of providers in app.config.ts Step 1:   To provide HttpClient in a standalone app we could do this in the app.config.ts file, app.config.ts: import { ApplicationConfig } from '@angular/core'; import { provideRouter } from '@angular/router'; import { routes } from './app.routes'; import { provideClientHydration } from '@angular/platform-browser'; //This (provideHttpClient) will help us to resolve the issue  import {provideHttpClient} from '@angular/common/http'; export const appConfig: ApplicationConfig = {   providers: [ provideRouter(routes),  provideClientHydration(), provideHttpClient ()      ] }; The appConfig const is used in the main.ts file, see the code, main.ts : import { bootstrapApplication } from '@angular/platform-browser'; import { appConfig } from '

List of Countries, Nationalities and their Code In Excel File

Download JSON file for this List - Click on JSON file    Countries List, Nationalities and Code Excel ID Country Country Code Nationality Person 1 UNITED KINGDOM GB British a Briton 2 ARGENTINA AR Argentinian an Argentinian 3 AUSTRALIA AU Australian an Australian 4 BAHAMAS BS Bahamian a Bahamian 5 BELGIUM BE Belgian a Belgian 6 BRAZIL BR Brazilian a Brazilian 7 CANADA CA Canadian a Canadian 8 CHINA CN Chinese a Chinese 9 COLOMBIA CO Colombian a Colombian 10 CUBA CU Cuban a Cuban 11 DOMINICAN REPUBLIC DO Dominican a Dominican 12 ECUADOR EC Ecuadorean an Ecuadorean 13 EL SALVADOR