diff --git a/aio/content/guide/npm-packages.md b/aio/content/guide/npm-packages.md index 530f841288..8543f3556e 100644 --- a/aio/content/guide/npm-packages.md +++ b/aio/content/guide/npm-packages.md @@ -1,16 +1,18 @@ # Npm Packages -Angular applications and Angular itself depend upon features and functionality provided by a variety of third-party packages. -These packages are maintained and installed with the Node Package Manager (npm). + The [**Angular CLI**](https://cli.angular.io/), Angular applications, and Angular itself depend upon features and functionality provided by libraries that are available as [**npm**](https://docs.npmjs.com/) packages. + +You can download and install these npm packages with the [**npm client**](https://docs.npmjs.com/cli/install), which runs as a node.js application. + +The [**yarn client**](https://yarnpkg.com/en/) is a popular alternative for downloading and installing npm packages. +The Angular CLI uses `yarn` by default to install npm packages when you create a new project.
- - Node.js and npm are essential to Angular development. - -Get them now if they're not already installed on your machine. +[Get them now](https://docs.npmjs.com/getting-started/installing-node "Installing Node.js and updating npm") +if they're not already installed on your machine. **Verify that you are running node `v4.x.x` or higher and npm `3.x.x` or higher** by running the commands `node -v` and `npm -v` in a terminal/console window. @@ -20,244 +22,152 @@ Consider using [nvm](https://github.com/creationix/nvm) for managing multiple versions of node and npm. You may need [nvm](https://github.com/creationix/nvm) if you already have projects running on your machine that use other versions of node and npm. -
+## _package.json_ +Both `npm` and `yarn` install packages identified in a [**package.json**](https://docs.npmjs.com/files/package.json) file. -During [Setup](guide/setup), a package.json -file is installed with a comprehensive starter set of -packages as specified in the `dependencies` and `devDependencies` sections. +The CLI `ng new` command creates a default `packages.json` file for your project. +This `packages.json` specifies _a starter set of packages_ that work well together and +jointly support many common application scenarios. -You can use other packages but the packages in _this particular set_ work well together and include -everything you need to build and run the sample applications in this series. +You will add packages to `packages.json` as your application evolves. +You may even remove some. +This guide focuses on the most important packages in the starter set. -
+#### *dependencies* and *devDependencies* - - -Note: A cookbook or guide page may require an additional library such as *jQuery*. - -
- - - -You'll install more than you need for the QuickStart guide. -No worries! -You only serve to the client those packages that the application actually requests. - -This page explains what each package does. You can make substitutions later to suit your tastes and experience. - - - -## *dependencies* and *devDependencies* The `package.json` includes two sets of packages, [dependencies](guide/npm-packages#dependencies) and [devDependencies](guide/npm-packages#dev-dependencies). The *dependencies* are essential to *running* the application. The *devDependencies* are only necessary to *develop* the application. -You can exclude them from production installations by adding `--production` to the install command, as follows: - - - npm install my-application --production - - - - {@a dependencies} - - -## *dependencies* +## *Dependencies* The `dependencies` section of `package.json` contains: -* ***Features***: Feature packages give the application framework and utility capabilities. +* **Angular packages**: Angular core and optional modules; their package names begin `@angular/`. -* ***Polyfills***: Polyfills plug gaps in the browser's JavaScript implementation. +* **Support packages**: 3rd party libraries that must be present for Angular apps to run. -* ***Other***: Other libraries that support the application such as `bootstrap` for HTML widgets and styling. +* **Polyfill packages**: Polyfills plug gaps in a browser's JavaScript implementation. +### Angular Packages +**@angular/animations**: Angular's animations library makes it easy to define and apply animation effects such as page and list transitions. +Read about it in the [Animations guide](guide/animations). -### Feature Packages +**@angular/common**: The commonly needed services, pipes, and directives provided by the Angular team. +The [`HttpClientModule`](guide/http) is also here, in the '@angular/common/http' subfolder. -***@angular/core***: Critical runtime parts of the framework needed by every application. +**@angular/core**: Critical runtime parts of the framework needed by every application. Includes all metadata decorators, `Component`, `Directive`, dependency injection, and the component lifecycle hooks. -***@angular/common***: The commonly needed services, pipes, and directives provided by the Angular team. - -***@angular/compiler***: Angular's *Template Compiler*. +**@angular/compiler**: Angular's *Template Compiler*. It understands templates and can convert them to code that makes the application run and render. -Typically you don’t interact with the compiler directly; rather, you use it indirectly via `platform-browser-dynamic` or the offline template compiler. +Typically you don’t interact with the compiler directly; rather, you use it indirectly via `platform-browser-dynamic` when [JIT compiling](guide/aot-compiler) in the browser. -***@angular/platform-browser***: Everything DOM and browser related, especially +**@angular/forms**: support for both [template-driven](guide/forms) and [reactive forms](guide/reactive-forms). + +**@angular/http**: Angular's old, soon-to-be-deprecated, HTTP client. + +**@angular/platform-browser**: Everything DOM and browser related, especially the pieces that help render into the DOM. This package also includes the `bootstrapStatic()` method -for bootstrapping applications for production builds that pre-compile templates offline. +for bootstrapping applications for production builds that pre-compile with [AOT](guide/aot-compiler). -***@angular/platform-browser-dynamic***: Includes [Providers](api/core/Provider) -and a [bootstrap](guide/ngmodule#bootstrap) method for applications that -compile templates on the client. Don’t use offline compilation. -Use this package for bootstrapping during development and for bootstrapping plunker samples. - -***@angular/http***: Angular's HTTP client. - -***@angular/router***: Component router. - -***@angular/upgrade***: Set of utilities for upgrading AngularJS applications to Angular. - -***[system.js](https://github.com/systemjs/systemjs)***: A dynamic module loader compatible with the -[ES2015 module](http://www.2ality.com/2014/09/es6-modules-final.html) specification. -Other viable choices include the well-regarded [webpack](https://webpack.github.io/). - -Your future applications are likely to require additional packages that provide -HTML controls, themes, data access, and various utilities. +**@angular/platform-browser-dynamic**: Includes [Providers](api/core/Provider) +and methods to compile and run the app on the client +using the [JIT compiler](guide/aot-compiler). +**@angular/router**: The [router module](/guide/router) navigates among your app pages when the browser URL changes. +**@angular/upgrade**: Set of utilities for upgrading AngularJS applications to Angular. {@a polyfills} - - ### Polyfill packages -Angular requires certain [polyfills](https://en.wikipedia.org/wiki/Polyfill) in the application environment. -Install these polyfills using the npm packages that Angular lists in the *peerDependencies* section of its `package.json`. +Many browsers lack native support for some features in the latest HTML standards, +features that Angular requires. +"[Polyfills](https://en.wikipedia.org/wiki/Polyfill)" can emulate the missing features. +The [Browser Support](guide/browser-support) guide explains which browsers need polyfills and +how you can add them. -You must list these packages in the `dependencies` section of your own `package.json`. +The default `package.json` installs the **[core-js](https://github.com/zloirock/core-js)** package +which polyfills missing features for several popular browser. +### Support packages -
- - - -For background on this requirement, see [Why peerDependencies?](guide/npm-packages#why-peer-dependencies). - -
- - - -***core-js***: Patches the global context (window) with essential features of ES2015 (ES6). - You may substitute an alternative polyfill that provides the same core APIs. - When these APIs are implemented by the major browsers, this dependency will become unnecessary. - -***rxjs***: A polyfill for the [Observables specification](https://github.com/zenparsing/es-observable) currently before the +**[rxjs](https://github.com/benlesh/RxJS)**: Many Angular APIs return _observables_. RxJS is an implementation of the proposed [Observables specification](https://github.com/zenparsing/es-observable) currently before the [TC39](http://www.ecma-international.org/memento/TC39.htm) committee that determines standards for the JavaScript language. -You can pick a preferred version of *rxjs* (within a compatible version range) -without waiting for Angular updates. -***zone.js***: A polyfill for the [Zone specification](https://gist.github.com/mhevery/63fdcdf7c65886051d55) currently before the + +**[zone.js](https://github.com/angular/zone.js)**: Angular relies on zone.js to run Angular's change detection processes when native JavaScript operations raise events. Zone.js is an implementation of a [specification](https://gist.github.com/mhevery/63fdcdf7c65886051d55) currently before the [TC39](http://www.ecma-international.org/memento/TC39.htm) committee that determines standards for the JavaScript language. -You can pick a preferred version of *zone.js* to use (within a compatible version range) -without waiting for Angular updates. - - -{@a other} - - - -### Other helper libraries - -***angular-in-memory-web-api***: An Angular-supported library that simulates a remote server's web api -without requiring an actual server or real HTTP calls. -Good for demos, samples, and early stage development (before you even have a server). - -***bootstrap***: [Bootstrap](http://getbootstrap.com/) is a popular HTML and CSS framework for designing responsive web apps. -Some of the samples improve their appearance with *bootstrap*. {@a dev-dependencies} +## *DevDependencies* + +The packages listed in the *devDependencies* section of the `package.json` help you develop the application on your local machine. + +You don't deploy them with the production application although there is no harm in doing so. + +**[@angular/cli](https://github.com/angular/angular-cli/)**: The Angular CLI tools. -## *devDependencies* -The packages listed in the *devDependencies* section of the `package.json` help you develop the application. -You don't have to deploy them with the production application although there is no harm in doing so. +**[@angular/compiler-cli](https://github.com/angular/angular/blob/master/packages/compiler-cli/README.md)**: The Angular compiler, which is invoked by the Angular CLI's `build` and `serve` commands. -***[concurrently](https://www.npmjs.com/package/concurrently)***: -A utility to run multiple *npm* commands concurrently on OS/X, Windows, and Linux operating systems. -***[lite-server](https://www.npmjs.com/package/lite-server)***: -A light-weight, static file server, by [John Papa](http://johnpapa.net/) -with excellent support for Angular apps that use routing. +**[@angular/language-service](https://github.com/angular/angular-cli/)**: The Angular language service analyzes component templates and provides type and error information that TypeScript-aware editors can use to improve the developer's experience. +For example, see the [Angular language service extension for VS Code](https://marketplace.visualstudio.com/items?itemName=Angular.ng-template) -***[typescript](https://www.npmjs.com/package/typescript)***: + +**@types/... **: TypeScript definition files for 3rd party libraries such as Jasmine and node. + + +**[codelyzer](https://www.npmjs.com/package/codelyzer)**: A linter for Angular apps whose rules conform to the Angular [style guide](guide/styleguide). + + +**jasmine/... **: packages to support the [Jasmine](https://jasmine.github.io/) test library. + + +**karma/... **: packages to support the [karma](https://www.npmjs.com/package/karma) test runner. + + +**[protractor](https://www.npmjs.com/package/protractor)**: an end-to-end (e2e) framework for Angular apps. +Built on top of [WebDriverJS](https://github.com/SeleniumHQ/selenium/wiki/WebDriverJs). + + +**[ts-node](https://www.npmjs.com/package/ts-node)**: TypeScript execution environment and REPL for node. + + +**[tslint](https://www.npmjs.com/package/tslint)**: a static analysis tool that checks TypeScript code for readability, maintainability, and functionality errors. + + +**[typescript](https://www.npmjs.com/package/typescript)**: the TypeScript language server, including the *tsc* TypeScript compiler. -***@types/\* ***: TypeScript definition files. -Learn more about it in the [TypeScript Configuration](guide/typescript-configuration#typings) guide. +## So many packages! So many files! +The default `package.json` installs more packages than you'll need for your project. -{@a why-peer-dependencies} +A given package may contain tens, hundreds, even thousands of files, +all of them in your local machine's `node_modules` directory. +The sheer volume of files is intimidating, +You can remove packages that you don't need but how can you be sure that you won't need it? +As a practical matter, it's better to install a package you don't need than worry about it. +Extra packages and package files on your local development machine are harmless. -## Why *peerDependencies*? - -There isn't a [*peerDependencies*](https://nodejs.org/en/blog/npm/peer-dependencies/) section in the QuickStart `package.json`. -But Angular has a *peerDependencies* section in -*its* `package.json`, which has important consequences for your application. - -This section explains why you load the [polyfill](guide/npm-packages#polyfills) *dependency* -packages in the QuickStart application's `package.json`, -and why you'll need those packages in your own applications. - -Packages depend on other packages. For example, your application depends on the Angular package. - -Two packages, "A" and "B", could depend on the same third package "C". -"A" and "B" might both list "C" among their *dependencies*. - -What if "A" and "B" depend on different versions of "C" ("C1" and "C2"). The npm package system supports that. -It installs "C1" in the `node_modules` folder for "A" and "C2" in the `node_modules` folder for "B". -Now "A" and "B" have their own copies of "C" and they run without interferring with one another. - -But there is a problem. Package "A" may require the presence of "C1" without actually calling upon it directly. -"A" may only work if *everyone is using "C1"*. It falls down if any part of the application relies on "C2". - -The solution is for "A" to declare that "C1" is a *peer dependency*. - -The difference between a `dependency` and a `peerDependency` is roughly this: - ->A **dependency** says, "I need this thing directly available to *me*." -> ->A **peerDependency** says, "If you want to use me, you need this thing available to *you*." - -The Angular `package.json` specifies several *peer dependency* packages, -each pinned to a particular version of a third-party package. - -### You must install Angular's *peerDependencies* yourself. - -When *npm* installs packages listed in *your* `dependencies` section, -it also installs the packages listed within *their* packages `dependencies` sections. -The process is recursive. - -However, as of version 3, *npm* does *not* install packages listed in *peerDependencies* sections. - -This means that when your application installs Angular, ***npm* doesn't automatically install -the packages listed in Angular's *peerDependencies* section**. - -Fortunately, *npm* issues a warning (a) When any *peer dependencies* are missing, or (b) -When the application or any of its other dependencies -installs a different version of a *peer dependency*. - -These warnings guard against accidental failures due to version mismatches. -They leave you in control of package and version resolution. - -It is your responsibility to list all *peer dependency* packages **among your own *devDependencies***. - - -
- - - -#### The future of *peerDependencies* - -The Angular polyfill dependencies are hard requirements. Currently, there is no way to make them optional. - -However, there is an npm feature request for "optional peerDependencies," which would allow you to model this relationship better. -When this feature request is implemented, Angular will switch from *peerDependencies* to *optionalPeerDependencies* for all polyfills. - -
+By default the Angular CLI build process bundles into a single file just the few "vendor" library files that your application actually needs. +The browser downloads this bundle, not the original package files. +See the [Deployment](guide/deployment) to learn more.