Angular ng generate

The ng generate command is one of the most commonly used commands in Angular CLI. It is used to generate various Angular elements like components, services, modules, pipes, and more. This command helps maintain consistency across the project by automatically creating the necessary files and updating relevant parts of the application.

Benefits of Using ng generate in Angular

Some key benefits of using ng generate in Angular are:

• Consistency Across the Codebase: ng generate ensures that all generated components, services, modules, and other elements follow a consistent naming convention and file structure.
• Enhanced Productivity: Manually creating files and writing boilerplate code can be time-consuming. ng generate speed up the development process by automating these tasks, allowing developers to focus on writing the actual business logic and features of the application.
• Built-In Best Practices: Angular CLI and ng generate adhere to Angular’s recommended best practices. The generated code is scaffolded with the appropriate structure, imports, and configurations, helping developers follow industry standards effortlessly.

Prerequisites

• Basic Knowledge of HTML, CSS and JavaScript
• Angular CLI

Basic Command Syntax

1. Understanding the Basic Syntax

ng generate <schematic> [name] [options]

• ng generate: The command to generate Angular elements such as components, services, modules, etc.
• <schematic>: Specifies what you want to generate. Common schematics include:
  • component: Generates a new component.
  • service: Generates a new service.
  • module: Generates a new module.
  • directive: Generates a new directive.
  • pipe: Generates a new pipe.
  • class: Generates a new class.
  • guard: Generates a new guard.

• <name>: The name of the element you want to generate. This should follow Angular's naming conventions.
• [options]: Optional flags that can modify the behavior of the generation process. Some commonly used options include:
  • --inline-template: Generates a component with an inline HTML template.
  • --inline-style: Generates a component with inline CSS styles.
  • --skip-tests: Skips generating the associated test files.
  • --module=<module-name>: Specifies the module to declare the new component in.

Sub-Commands Overview

1. app-shell

It generates an App Shell for the application. App Shell is a way to improve the perceived loading performance of your application by rendering a simple shell (basic UI) before the full application loads.

Command:

ng generate app-shell

2. application

It generates a new application within a workspace. It is iseful when working with Angular workspaces that host multiple applications.

Command:

ng generate application <application-name>

3. Component

It generates a new Angular component. This command generates all necessary files and updates the module declarations automatically.

Command:

ng generate component <component-name>

4. directive

It generates a new Angular directive. This command creates the directive file and a corresponding test file.

Command:

ng generate directive <directive-name>

5. module

It generates a new Angular module.Modules are used to group related components, directives, and services. This command generates the module file and optionally includes routing setup.

Command:

ng generate module <module-name>

6. resolver

It generates a new Angular resolver. Resolvers are used to fetch data before a route is activated. This command creates the resolver service that implements the necessary interface.

Command:

ng generate resolver <resolver-name>

7. service

It generates a new Angular service. Services are used to encapsulate business logic and data access. This command creates the service file and a corresponding test file.

Command:

ng generate service <service-name>

8. service-worker

It generates files necessary to add service worker support to your application. Service workers are used for offline capabilities and caching in Angular applications. This command configures your project to support service workers.

Command:

ng generate service-worker

9. web-worker

It generates a new web worker. Web workers are used to run scripts in background threads, improving the performance of CPU-intensive tasks. This command generates the necessary files to add a web worker.

Command:

ng generate web-worker <worker-name>

Generating Components

The ng generate component command in Angular CLI is used to create a new Angular component. This command generates all the necessary files and boilerplate code, saving time and ensuring consistency across the project.

Syntax

ng generate component <component-name>

Options and Flags for Generating Components

1. --inline-template (-t): It generates the component with an inline HTML template instead of a separate .html file.

Syntax:

ng g c <component-name> --inline-template

2. --inline-style (-s): It generates the component with inline CSS styles instead of a separate .css (or .scss, .less, etc.) file.

Syntax:

ng g c <component-name> --inline-style

3. --skip-tests (-t): It skips the generation of the test file (.spec.ts) for the component.

Syntax:

ng g c <component-name> --skip-tests

4. --module=<module-name> (-m): It specifies the module to declare the new component in. If not specified, Angular will automatically declare it in the nearest module.

Syntax:

ng g c <component-name> --module=app

Generating Services

The ng generate service command in Angular CLI is used to create a new service in an Angular application. A service is typically used to encapsulate business logic, handle data retrieval, and provide shared functionality across different parts of the application.

Syntax

ng generate service <service-name>

Options and Flags for Generating Services

1. --skip-tests (-t)

It skips the generation of the test file (.spec.ts) for the service.

Syntax:

ng g s <service-name> --skip-tests

2. --flat

It creates the service file without a dedicated subfolder. By default, Angular creates a subfolder with the service’s name to store all the files.

Syntax:

ng g s <service-name> --flat

3. --module=<module-name> (-m)

It specifies the module to provide the new service in. This option is typically used when the service should be provided in a specific module rather than globally.

Syntax:

ng g s <service-name> --module=app

Generating Modules

The ng generate module command in Angular CLI is used to create a new module in an Angular application. Modules are used to group related components, services, directives, and pipes, allowing for better organization and modularization of the application.

Syntax

ng generate module <module-name>

Options and Flags for Generating Modules

1. --routing (-r)

It adds a routing module file along with the main module file. This is useful when creating a feature module that requires its own routing configuration.

Syntax:

ng g m <module-name> --routing

2. --module=<module-name> (-m)

It specifies the parent module where the new module should be imported. This is useful for adding a feature module to a specific parent module automatically.

Syntax:

ng g m <module-name> --module=app

3. --flat

It creates the module file without a dedicated subfolder. By default, Angular creates a subfolder with the module’s name to store all the files.

Syntax:

ng g m <module-name> --flat

4. --route=<route>

It adds the module to the Angular router configuration with the specified route. This is typically used in conjunction with the --module option.

Syntax:

ng g m <module-name> --route=<route> --module=app

Generating Directives

The ng generate directive command in Angular CLI is used to create a new directive in an Angular application. Directives are classes that can modify the behavior or appearance of elements in your Angular templates.

Syntax

ng generate directive <directive-name>

Options and Flags for Generating Directives

When generating a directive, several options and flags can be used to customize the output:

1. --skip-tests (-t)

It skips the generation of the test file (.spec.ts) for the directive.

Syntax:

ng g d <directive-name> --skip-tests

2. --flat

It creates the directive file without a dedicated subfolder. By default, Angular creates a subfolder with the directive’s name to store all the files.

Syntax:

ng g d <directive-name> --flat

3. --module=<module-name> (-m)

It specifies the module where the new directive should be declared. This option automatically adds the directive to the specified module’s declarations array.

Syntax:

ng g d <directive-name> --module=<module-name>

Generating Pipes

The ng generate pipe command in Angular CLI is used to create a new pipe in an Angular application. Pipes transform data before displaying it in the view, making it easy to format, filter, or modify data within templates.

Syntax

ng generate pipe <pipe-name>

Options and Flags for Generating Pipes

When generating a pipe, several options and flags can be used to customize the output:

1. --skip-tests (-t)

It skips the generation of the test file (.spec.ts) for the pipe.

Syntax:

ng g p <pipe-name> --skip-tests

2. --flat

It creates the pipe file without a dedicated subfolder. By default, Angular creates a subfolder with the pipe’s name to store all the files.

Syntax:

ng g p <pipe-name> --flat

3. --module=<module-name> (-m)

It specifies the module where the new pipe should be declared. This option automatically adds the pipe to the specified module’s declarations array.

Syntax:

ng g p <pipe-name> --module=<module-name>

Generating Guards

The ng generate guard command in Angular CLI is used to create a new guard in an Angular application. Guards are used to control access to routes based on specific conditions, such as user authentication or authorization.

Syntax

ng generate guard <guard-name>

Options and Flags for Generating Guards

When generating a guard, several options and flags can be used to customize the output:

1. --skip-tests (-t)

It skips the generation of the test file (.spec.ts) for the guard.

Syntax:

ng g g <guard-name> --skip-tests

2. --implements

• Description: Specifies which guard interfaces to implement. Angular provides four types of guards:
• CanActivate: Checks if a route can be activated.
• CanActivateChild: Checks if a child route can be activated.
• CanDeactivate: Checks if a route can be deactivated.
• CanLoad: Checks if a module can be loaded.

Syntax:

ng g g <guard-name> --implements=CanActivate

You can also implement multiple guards by separating them with commas:

ng g g <guard-name> --implements=CanActivate,CanLoad

Generating Other Schematics

Angular CLI provides a range of schematics for generating various elements in an Angular project. Beyond the commonly used components, services, and modules, there are several less common schematics that can be useful for specific tasks.

Overview of Less Common Schematics

• enum: Generates an enum TypeScript file. Enums are a way to define a set of named constants, which can be useful for defining a fixed set of related values.
• resolver: Generates a route resolver. Route resolvers are used to pre-fetch data before navigating to a route.
• interceptor: Generates an HTTP interceptor. Interceptors allow you to modify HTTP requests and responses globally.
• service-worker: Generates a service worker configuration. Service workers are used for creating Progressive Web Apps (PWAs) and handling caching.
• web-worker: Generates a web worker. Web workers run scripts in background threads to perform computationally heavy tasks without blocking the main thread.

Steps to set up an Angular Application

Step 1: Install Angular CLI

npm install -g @angular/cli

Step 2: Create a New Angular Project

ng new component
cd component

Folder Structure

Dependencies

"dependencies": {
    "@angular/animations": "^18.2.0",
    "@angular/common": "^18.2.0",
    "@angular/compiler": "^18.2.0",
    "@angular/core": "^18.2.0",
    "@angular/forms": "^18.2.0",
    "@angular/platform-browser": "^18.2.0",
    "@angular/platform-browser-dynamic": "^18.2.0",
    "@angular/platform-server": "^18.2.0",
    "@angular/router": "^18.2.0",
    "@angular/ssr": "^18.2.0",
    "express": "^4.18.2",
    "rxjs": "~7.8.0",
    "tslib": "^2.3.0",
    "zone.js": "~0.14.10"
}

Step 3: Create a Component

Create a component. You can generate a component using the Angular CLI:

ng generate component  example

Example: We will be generating a component named as 'example' which will be added in the app.component HTML as a selector in order to demonstrate example component in browser.

App Component

Below is the code example of app component which is a standalone component having selector of example component which will be displayed on the browser followed by its subsequent imports in imports array of typescript file.

<!-- src/app/app.component.html -->
<app-example></app-example>

//src/app/app.component.ts
import { Component } from '@angular/core';
import { RouterOutlet } from '@angular/router';
import { ExampleComponent } from "./example/example.component";

@Component({
    selector: 'app-root',
    standalone: true,
    imports: [RouterOutlet, ExampleComponent],
    templateUrl: './app.component.html',
    styleUrl: './app.component.css'
})
export class AppComponent {
    title = 'component';
}

Example Component

Below is the code example of example component which is used as an example for demonstarting the working and setup of components in angular.

<!-- src/app/example/example.component.html -->
<p>example works!</p>

//src/app/example/example.component.ts
import { Component } from '@angular/core';

@Component({
    selector: 'app-example',
    standalone: true,
    imports: [],
    templateUrl: './example.component.html',
    styleUrl: './example.component.css'
})
export class ExampleComponent {

}

Output:

Conclusion

The ng generate command in Angular is a powerful tool that streamlines the development process by automating the creation of various components, services, modules, and more. By following best practices and leveraging the full range of available options, you can maintain a clean, efficient, and well-structured codebase. Whether you're generating standard Angular constructs or integrating custom schematics, ng generate helps enforce Angular's conventions while saving time and reducing errors.