Before fully deploying your application, you can test the process, build configuration, and deployed behavior by using one of these interim techniques.
During development, you typically use the `ng serve` command to build, watch, and serve the application from local memory, using [webpack-dev-server](https://webpack.js.org/guides/development/#webpack-dev-server).
When you are ready to deploy, however, you must use the `ng build` command to build the app and deploy the build artifacts elsewhere.
Both `ng build` and `ng serve` clear the output folder before they build the project, but only the `ng build` command writes the generated build artifacts to the output folder.
<divclass="alert is-helpful">
The output folder is `dist/project-name/` by default.
To output to a different folder, change the `outputPath` in `angular.json`.
</div>
As you near the end of the development process, serving the contents of your output folder from a local web server can give you a better idea of how your application will behave when it is deployed to a remote server.
You will need two terminals to get the live-reload experience.
* On the first terminal, run the [`ng build` command](cli/build) in *watch* mode to compile the application to the `dist` folder.
Like the `ng serve` command, this regenerates output files when source files change.
* On the second terminal, install a web server (such as [lite-server](https://github.com/johnpapa/lite-server)), and run it against the output folder. For example:
The Angular CLI command `ng deploy` (introduced in version 8.3.0) executes the `deploy` [CLI builder](guide/cli-builder) associated with your project. A number of third-party builders implement deployment capabilities to different platforms. You can add any of them to your project by running `ng add [package name]`.
When you add a package with deployment capability, it'll automatically update your workspace configuration (`angular.json` file) with a `deploy` section for the selected project. You can then use the `ng deploy` command to deploy that project.
The command is interactive. In this case, you must have or create a Firebase account, and authenticate using that account. The command prompts you to select a Firebase project for deployment
In the table below, you can find a list of packages which implement deployment functionality to different platforms. The `deploy` command for each package may require different command line options. You can read more by following the links associated with the package names below:
If you're deploying to a self-managed server or there's no builder for your favorite cloud platform, you can either create a builder that allows you to use the `ng deploy` command, or read through this guide to learn how to manually deploy your app.
1. You need to [create a GitHub account](https://github.com/join) if you don't have one, and then [create a repository](https://help.github.com/articles/create-a-repo/) for your project.
1. On the GitHub project page, configure it to [publish from the docs folder](https://help.github.com/articles/configuring-a-publishing-source-for-github-pages/#publishing-your-github-pages-site-from-a-docs-folder-on-your-master-branch).
You can see your deployed page at `https://<user_name>.github.io/<project_name>/`.
Check out [angular-cli-ghpages](https://github.com/angular-buch/angular-cli-ghpages), a full featured package that does all this for you and has extra functionality.
* [Ruby](https://www.ruby-lang.org/): create a Ruby server using ([sinatra](http://sinatrarb.com/)) with a basic Ruby file that configures the server `server.rb`:
the GitHub Pages server, but you can add a 404 page.
Copy `index.html` into `404.html`.
It will still be served as the 404 response, but the browser will process that page and load the app properly.
It's also a good idea to
[serve from `docs/` on master](https://help.github.com/articles/configuring-a-publishing-source-for-github-pages/#publishing-your-github-pages-site-from-a-docs-folder-on-your-master-branch)
and to
[create a `.nojekyll` file](https://www.bennadel.com/blog/3181-including-node-modules-and-vendors-folders-in-your-github-pages-site.htm)
* [Firebase hosting](https://firebase.google.com/docs/hosting/): add a
In addition to build optimizations, Angular also has a runtime production mode. Angular apps run in development mode by default, as you can see by the following message on the browser console:
Even as JavaScript continues to evolve, with new features being introduced, not all browsers are updated with support for these new features at the same pace.
The code you write in development using TypeScript is compiled and bundled into ES2015, the JavaScript syntax that is compatible with most browsers.
All modern browsers support ES2015 and beyond, but in most cases, you still have to account for users accessing your application from a browser that doesn't.
When targeting older browsers, [polyfills](guide/browser-support#polyfills) can bridge the gap by providing functionality that doesn't exist in the older versions of JavaScript supported by those browsers.
Differential loading is a strategy that allows your web application to support multiple browsers, but only load the necessary code that the browser needs. When differential loading is enabled the CLI builds two separate bundles as part of your deployed application.
* The first bundle contains modern ES2015 syntax. This bundle takes advantage of built-in support in modern browsers, ships fewer polyfills, and results in a smaller bundle size.
* The second bundle contains code in the old ES5 syntax, along with all necessary polyfills. This second bundle is larger, but supports older browsers.
When you deploy using the Angular CLI build process, you can choose how and when to support differential loading.
The [`ng build` CLI command](cli/build) queries the browser configuration and the configured build target to determine if support for legacy browsers is required, and whether the build should produce the necessary bundles used for differential loading.
The Browserslist configuration file is included in your application [project structure](guide/file-structure#application-configuration-files) and provides the minimum browsers your application supports. See the [Browserslist spec](https://github.com/browserslist/browserslist) for complete configuration options.
In the TypeScript configuration file, the "target" option in the `compilerOptions` section determines the ECMAScript target version that the code is compiled to.
Differential loading is currently only supported when using `es2015` as a compilation target. When used with targets higher than `es2015`, the build process emits a warning.
For a production build, your configuration determines which bundles are created for deployment of your application.
When needed, the `index.html` file is also modified during the build process to include script tags that enable differential loading, as shown in the following example.
Each script tag has a `type="module"` or `nomodule` attribute. Browsers with native support for ES modules only load the scripts with the `module` type attribute and ignore scripts with the `nomodule` attribute. Legacy browsers only load the scripts with the `nomodule` attribute, and ignore the script tags with the `module` type that load ES modules.
Some legacy browsers still download both bundles, but only execute the appropriate scripts based on the attributes mentioned above. You can read more on the issue [here](https://github.com/philipwalton/webpack-esnext-boilerplate/issues/1).
To include differential loading in your application builds, you must configure the Browserslist and TypeScript configuration files in your application project.
The following examples show a `.browserslistrc` and `tsconfig.json` file for a newly created Angular application. In this configuration, legacy browsers such as IE 9-11 are ignored, and the compilation target is ES2015.
To see which browsers are supported and determine which settings meet to your browser support requirements, see the [Browserslist compatibility page](https://browserl.ist/?q=%3E+0.5%25%2C+last+2+versions%2C+Firefox+ESR%2C+not+dead%2C+not+IE+9-11).
If your Browserslist configuration includes support for any legacy browsers, the build target in the TypeScript configuration determines whether the build will support differential loading.
In Angular CLI version 8 and higher, differential loading is enabled by default for the `ng build` command.
The `ng serve`, `ng test`, and `ng e2e` commands, however, generate a single ES2015 build which cannot run in older browsers that don't support the modules, such as IE 11.
If you want to run ES5 code during development, you could disable differential loading completely.
To maintain the benefits of differential loading, however, a better option is to define multiple configurations for `ng serve`, `ng e2e`, and `ng test`.
You can then run the `ng serve` command with this configuration. Make sure to replace `<app-name>` (in `"<app-name>:build:es5"`) with the actual name of the app, as it appears under `projects` in `angular.json`. For example, if your app name is `myAngularApp` the config will become `"browserTarget": "myAngularApp:build:es5"`.
Create an [ES5 serve configuration](guide/deployment#configuring-serve-for-es5) as explained above, and configuration an ES5 configuration for the E2E target.
You can then run the `ng e2e` command with this configuration. Make sure to replace `<app-name>` (in `"<app-name>:serve:es5"`) with the actual name of the app, as it appears under `projects` in `angular.json`. For example, if your app name is `myAngularApp` the config will become `"devServerTarget": "myAngularApp:serve:es5"`.
