angular-cn/aio/content/guide/setup-local.md

Setting up the local environment and workspace

This guide explains how to set up your environment for Angular development using the Angular CLI tool. It includes information about prerequisites, installing the CLI, creating an initial workspace and starter app, and running that app locally to verify your setup.

Try Angular without local setup

If you are new to Angular, you might want to start with Try it now!, which introduces the essentials of Angular in the context of a ready-made basic online store app that you can examine and modify. This standalone tutorial takes advantage of the interactive StackBlitz environment for online development. You don't need to set up your local environment until you're ready.

{@a devenv} {@a prerequisites}

Prerequisites

To use the Angular framework, you should be familiar with the following:

• JavaScript
• HTML
• CSS

Knowledge of TypeScript is helpful, but not required.

To install Angular on your local system, you need the following:

{@a nodejs}

• Node.js

  Angular requires a current, active LTS, or maintenance LTS version of Node.js.

  For information about specific version requirements, see the engines key in the package.json file.

  For more information on installing Node.js, see nodejs.org. If you are unsure what version of Node.js runs on your system, run node -v in a terminal window.

{@a npm}

• npm package manager

  Angular, the Angular CLI, and Angular applications depend on npm packages for many features and functions. To download and install npm packages, you need an npm package manager. This guide uses the npm client command line interface, which is installed with Node.js by default. To check that you have the npm client installed, run npm -v in a terminal window.

{@a install-cli}

Install the Angular CLI

You use the Angular CLI to create projects, generate application and library code, and perform a variety of ongoing development tasks such as testing, bundling, and deployment.

To install the Angular CLI, open a terminal window and run the following command:

npm install -g @angular/cli

{@a create-proj}

Create a workspace and initial application

You develop apps in the context of an Angular workspace.

To create a new workspace and initial starter app:

1. Run the CLI command ng new and provide the name my-app, as shown here:

   ng new my-app

2. The ng new command prompts you for information about features to include in the initial app. Accept the defaults by pressing the Enter or Return key.

The Angular CLI installs the necessary Angular npm packages and other dependencies. This can take a few minutes.

The CLI creates a new workspace and a simple Welcome app, ready to run.

You also have the option to use Angular's strict mode, which can help you write better, more maintainable code. For more information, see Strict mode.

{@a serve}

Run the application

The Angular CLI includes a server, so that you can build and serve your app locally.

1. Navigate to the workspace folder, such as my-app.

2. Run the following command:

cd my-app ng serve --open

The ng serve command launches the server, watches your files, and rebuilds the app as you make changes to those files.

The --open (or just -o) option automatically opens your browser to http://localhost:4200/.

If your installation and setup was successful, you should see a page similar to the following.

Next steps

• For a more thorough introduction to the fundamental concepts and terminology of Angular single-page app architecture and design principles, read the Angular Concepts section.

• Work through the Tour of Heroes Tutorial, a complete hands-on exercise that introduces you to the app development process using the Angular CLI and walks through important subsystems.

• To learn more about using the Angular CLI, see the CLI Overview. In addition to creating the initial workspace and app scaffolding, you can use the CLI to generate Angular code such as components and services. The CLI supports the full development cycle, including building, testing, bundling, and deployment.

• For more information about the Angular files generated by ng new, see Workspace and Project File Structure.