Angular CLI tutorial

The Angular CLI is a command line interface for Angular developed by Angular Team. This tool helps us quickly get started with the creating the Angular Application. In this tutorial, we will learn how to create & Manage the Angular app using the Angular CLI commands. We will be covering the commands like ng new, ng generate component, ng generate directive & ng generate pipe etc.

Applies to: Angular 2, Angular 4, Angular 5, Angular 6, Angular 7, Angular 8

Why Angular CLI

Angular is easy to learn Front End Framework. But setting development environment is pretty complicated. There are many decisions, you have when you choose Angular as your JavaScript Framework.

You have an option of choosing Javascript, Typescript or dart. You have to choose a module loader among SystemJs & Webpack etc. You need to pickup your testing Framework. We discussed all this in our tutorial Installing and Setting Up an Angular Development Environment

Once you make a choice, then you have set up a lot of libraries and packages. Each of these libraries comes with their own configuration files. For instance, you need to create Package.Json file and add all the required libraries. Create Webpack or SystemJS configuration files. Configuration files are also required for Typescript & Typings etc. You need to configure the Testing Framework also.

Instead, you can install Angular CLI and get started right away.

Recommended Books:

The Best Books On Angular.

The 8 Best Angular Books, which helps you to get started with Angular. 

What is Angular CLI

The Angular CLI help you to quickly create an Angular application with all the configuration files and packages in one single command. It also helps us to add features (components, directives, services etc) to existing Angular applications.It helps us to test , build & distribute our application

The Angular CLI creates the Angular Application and uses Typescript, Webpack ( for Module bundling), Karma ( for unit testing), Protractor ( for an end to end testing).

Installing Angular CLI

The first step is to install the Angular CLI. This can be done by using the following command.

npm install -g @angular/[email protected]

The above command installs the latest version of Angular CLI in your machine. Note that we have used the -g flag, (which stands for global) installs the Angular CLI system-wide so that you can use it in your all projects.

Angular CLI Versions

Since, the Angular Version 6, the Angular CLI follows the same Version No as the Angular. Hence for Angular 7, the corresponding version of the Angular CLI is 7. 

The Angular CLI version 1.7 was for Angular 5 and Angular CLI 1.4 was for Angular 4

You can keep track of the latest Angular CLI release from this link https://github.com/angular/angular-cli/releases

Angular CLI Version Check

You can find out the Current Installed Angular CLI Version by Using the Command

ng --version

The latest version as of writing this article is 7.0.6. The command above also gives the version of node installed in your system.

Angular CLI Commands

Getting Help

ng help

Getting help on individual commands us the syntax ng [command name] --help. For Example

ng add --help       //help on add command
ng new --help       //help on new command  

Creating the Application with ng new

The ng new command is used to create new folder and creates an App with the provided name.

ng new 

The command will ask you

• What name would you like to use for the project?
  Enter the name of the project here. “GettingStarted”
• Would you like to add Angular Routing?
  Answer this as Yes unless you do not want to add Angular Routing.
• Which stylesheet format would you like to use?
  You arrow keys to select the available options from CSS, SCSS, SASS, LESS, and Stylus

The above command will create a folder GettingStarted and copies all the required dependencies and configuration settings. The Angular CLI does the following

1. Creates a new directory GettingStarted is created
2. Downloads and installs Angular libraries and any other dependencies
3. Installs and configures TypeScript.
4. Installs and configures Karma & Protractor for testing
5. Initialises the Git.

Running the Application

To run the application cd into the folder and run either ng server or use npm start (which runs the ng serve behind the scene)

cd gettingStarted
ng serve         // or npm start  

Now open the browser and enter the URL http://localhost:4200/ and you should be able to see Welcome to GettingStarted! Message

ng new options

ng new example

//creates with new project with Style CSS
ng new gettingStarted --routing  --style CSS

//creates the new project with HelloWorld_root as the selector
ng new HelloWorld --routing  --style CSS -p HelloWorld

ng generate

ng generate <schematic> [options]
ng g <schematic> [options]

ng generate or (ng g) is used to generate component, module, class, pipes & directives etc. The following tables shows the list of artifacts that can be generated.

Common options

The following are the common options of the ng g command

Component

The following command generates the component.

ng g component <name> [options]

Examples

ng g component Hello

The above command does the following

• Creates the Hello folder under the src/app folder
• Create the HelloComponent along with CSS, Spec & Template file under the Hello folder
• Imports the HelloComponent in the root module and adds it to the declarations array
• The CSS selector use the format app-<name>. i.e app-hello

Run these commands from the root folder of the application.

ng g component --flat Hello does not create the hello folder. The component is created in the src/app folder.

ng g component --flat hello/hello creates the component under src/app/hello folder

ng g component --export hello adds the component to the exports metadata array of the module.

ng g component --prefix=myapp hello uses the CSS selector as myapp-hello.

ng g component --selector=hi --force hello uses the selector as hi

generate component inside module

ng g module account generates the code for account module

ng g component --module=account account/hello adds the component to the account module

ng g component --module=account hello this works provided the current directory is module directory i.e src/app/account

The following is the list of all available options

Directive

ng g directive <name> [options] is used to generate the directive. For Example ng g directive Some generates the Some.Directive.ts. The following code is generated. It also generates the some.directive.spec.ts

import { Directive } from '@angular/core';

@Directive({
  selector: '[appSome]'
})
export class SomeDirective {

  constructor() { }

}

The above command does not create the folder. You can use the ng g directive directive/Some, which will create the directive under the folder directive.

You can use the command ng g directive --flat=false Some, which will create the directive under the folder Some (folder name is same as the directive name)

You can use the --force flag to force overwriting of the files, if the files already exists

Use the--module flag to add the directive to a module other than the root module.

Use the --prefix or --selector flag to change the CSS Selctor.

You can use the --export & --skipImport to add the directive to exports and imports metadata of the module

The following is the complete list of available options

Pipe

ng generate pipe <name> [options] is used to generate the pipe. For Example ng g pipe Date generates the date.pipe.ts. The following code is generated. It also generates the date.pipe.ts.spec.ts

import { Pipe, PipeTransform } from '@angular/core';

@Pipe({
  name: 'date'
})
export class DatePipe implements PipeTransform {

  transform(value: any, args?: any): any {
    return null;
  }

}

The above command does not create the folder. You can use the ng g pipe pipes/Date, which will create the pipe under the folderpipes.

You can use the command ng g pipe --flat=false Date, which will create the pipe under the folder Date (folder name is same as the pipe name)

You can use the --force flag to force overwriting of the files, if the files already exists

Use the--module flag to add the pipe to a module other than the root module.

You can use the --export & --skipImport to add the directive to exports and imports metadata of the module

The following is the complete list of available options

Service

ng generate service <name> [options] is used to generate the service. For Example ng g service Data generates the data.service.ts &data.service.ts.spec.ts. The following is the sample code generated by the command

import { Injectable } from '@angular/core';

@Injectable({
  providedIn: 'root'
})
export class DataService {

  constructor() { }
}

The above command does not create the folder. You can use the ng g service services/Data, which will create the service under the folderservices.

You can use the command ng g service --flat=false Data, which will create the service under the folder Data (folder name is same as the service name)

class

ng generate class <name> [options] is used to generate the class. For Example ng g class customer generates the customer.ts in the current folder. The following is the sample code generated by the command

export class Customer {
}

Use the command ng g class class/customer to create the class under the class folder.

Module

use the ng g module <name> [options] command to generate the module. For Example ng g module account generates the account module under the folder src/app/account. The following code is generated

import { NgModule } from '@angular/core';
import { CommonModule } from '@angular/common';

@NgModule({
  declarations: [],
  imports: [
    CommonModule
  ]
})
export class AccountModule { }

ng g module account --module=app generates the account module and adds it to the imports metadata array of AppModule

ng g module account --routing=true --force. The --force flag overwrites the previously generated files. The --routing=true also creates the account-routing.module. The routes are registered with the forChild(routes)

ng g module account --force --routing=true --routingScope=Root registers the routes with the forRoot(routes)

Adding Components, Pipes, Directives to module

You can add component, directive, pipe & services to module by using the flag --module=[ModuleName] and naming the component as [ModuleName]/[ComponentnNme].

For Example, The following commands creats the account module and adds the HelloComponent, SomeDirective, DataSerivce & DatePipe to the module

ng g module account
ng g component --module=account account/hello
ng g directive --module=account --flat=false account/Some
ng g service --module=account --flat=false account/Data
ng g pipe --module=account --flat=false account/Date

The following is the list of all the available options

ng update

The ng update command updates or upgrades the angular application and its dependencies to the latest version. Click on how to upgrade Angular to latest version for more information

Resources

The Angular CLI Command Reference

Summary

The Angular CLI helps to increase productivity by helping us to quickly create the app and add the component, pipes, services & directives etc to the module. The Angular CLI has lot more commands like serve, build, test, lint, e2e etc, which help us to build and distribute the applications. We will cover those in one of the future tutorial.