Angular Application Structure

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You develop apps in the context of an Angular workspace. A workspace contains the files for one or more projects. A project is the set of files that comprise a standalone app, a library, or a set of end-to-end (e2e) tests.

The Angular CLI command ng new <project_name> gets you started. When you run this command, the CLI installs the necessary Angular npm packages and other dependencies in a new workspace, with a root folder named project_name. It also creates the following workspace and starter project files:

• An initial skeleton app project, also called project_name (in the src/ subfolder).
• An end-to-end test project (in the e2e/ subfolder).
• Related configuration files.

The initial app project contains a simple Welcome app, ready to run.

Workspace Files

The top level of the workspace contains a number of workspace-wide configuration files.

Workspace config files	Purpose
.editorconfig	Configuration for code editors.
.gitignore	Specifies intentionally untracked files that Git should ignore.
angular.json	CLI configuration defaults for all projects in the workspace, including configuration options for build, serve, and test tools that the CLI uses, such as TSLint, Karma, and Protractor.
node_modules	Provides npm packages to the entire workspace.
package.json	Configures npm package dependencies that are available to all projects in the workspace.
package-lock.json	Provides version information for all packages installed into node_modules by the npm client. See npm documentation for details. If you use the yarn client, this file will be yarn.lock instead.
tsconfig.json	Default TypeScript configuration for apps in the workspace, including TypeScript and Angular template compiler options. See TypeScript Configuration.
tslint.json	Default TSLint configuration for apps in the workspace.
README.md	Introductory documentation.

All projects within a workspace share a CLI configuration context. Project-specific TypeScript configuration files inherit from the workspace-wide tsconfig.*.json, and app-specific TSLint configuration files inherit from the workspace-wide tslint.json.

Default app project files

The CLI command ng new my-app creates a workspace folder named “my-app” and generates a new app skeleton. This initial app is the default app for CLI commands (unless you change the default after creating additional apps).

A newly generated app contains the source files for a root module, with a root component and template. When the workspace file structure is in place, you can use the ng generate command on the command line to add functionality and data to the initial app.

Besides using the CLI on the command line, you can also use an interactive development environment like Angular Console, or manipulate files directly in the app’s source folder and configuration files.

The src/ subfolder contains the source files (app logic, data, and assets), along with configuration files for the initial app. Workspace-wide node_modules dependencies are visible to this project.

App source & config files	Purpose
app/	Contains the component files in which your app logic and data are defined.
assets/	Contains image files and other asset files to be copied as-is when you build your application.
environments/	Contains build configuration options for particular target environments. By default there is an unnamed standard development environment and a production (“prod”) environment. You can define additional target environment configurations.
browserslist	Configures sharing of target browsers and Node.js versions among various front-end tools.
favicon.ico	An icon to use for this app in the bookmark bar.
index.html	The main HTML page that is served when someone visits your site. The CLI automatically adds all JavaScript and CSS files when building your app, so you typically don’t need to add any <script> or<link> tags here manually.
main.ts	The main entry point for your app. Compiles the application with the JIT compiler and bootstraps the application’s root module (AppModule) to run in the browser. You can also use the AOT compiler without changing any code by appending the –aot flag to the CLI build and serve commands.
polyfills.ts	Provides polyfill scripts for browser support.
styles.sass	Lists CSS files that supply styles for a project. The extension reflects the style preprocessor you have configured for the project.
test.ts	The main entry point for your unit tests, with some Angular-specific configuration. You don’t typically need to edit this file.
tsconfig.app.json	Inherits from the workspace-wide tsconfig.json file.
tsconfig.spec.json	Inherits from the workspace-wide tsconfig.json file.
tslint.json	Inherits from the workspace-wide tslint.json file.

Default app project e2e files

An e2e/ subfolder contains configuration and source files for a set of end-to-end tests that correspond to the initial app. Workspace-wide node_modules dependencies are visible to this project.

my-app/

e2e/                  (end-to-end test app for my-app)

src/                (app source files)

protractor.conf.js  (test-tool config)

tsconfig.e2e.json   (TypeScript config inherits from workspace tsconfig.json)

Project folders for additional apps and libraries

When you generate new projects in a workspace, the CLI creates a new workspace/projects folder, and adds the generated files there.

When you generate an app (ng generate application my-other-app), the CLI adds folders under projects/ for both the app and its corresponding end-to-end tests. Newly generated libraries are also added under projects/.

my-app/

…

projects/           (additional apps and libs)

my-other-app/     (a second app)

src/

(config files)

my-other-app-e2e/  (corresponding test app)

src/

(config files)

my-lib/            (a generated library)

(config files)

App source folder

Inside the src/ folder, the app/ folder contains your app’s logic and data. Angular components, templates, and styles go here. An assets/ subfolder contains images and anything else your app needs. Files at the top level of src/ support testing and running your app.

App source files	Purpose
app/app.component.ts	Defines the logic for the app’s root component, named AppComponent. The view associated with this root component becomes the root of the view hierarchy as you add components and services to your app.
app/app.component.html	Defines the HTML template associated with the root AppComponent.
app/app.component.css	Defines the base CSS stylesheet for the root AppComponent.
app/app.component.spec.ts	Defines a unit test for the root AppComponent.
app/app.module.ts	Defines the root module, named AppModule, that tells Angular how to assemble the application. Initially declares only the AppComponent. As you add more components to the app, they must be declared here.
assets/*	Contains image files and other asset files to be copied as-is when you build your application.

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