This document describes how to set up your development environment to build and test Angular, both JS and Dart versions. It also explains the basic mechanics of using git, node, and npm.

• Prerequisite Software
• Getting the Sources
• Environment Variable Setup
• Installing NPM Modules and Dart Packages
• Build commands
• Running Tests Locally
• Code Style
• Project Information
• CI using Travis
• Transforming Dart code
• Debugging

See the contribution guidelines if you'd like to contribute to Angular.

Before you can build and test Angular, you must install and configure the following products on your development machine:

• Git and/or the GitHub app (for Mac or Windows); GitHub's Guide to Installing Git is a good source of information.

• Node.js, (version >=5.4.1 <6) which is used to run a development web server, run tests, and generate distributable files. We also use Node's Package Manager, npm (version >=3.5.3 <4.0), which comes with Node. Depending on your system, you can install Node either from source or as a pre-packaged bundle.

• Optional: Dart (version >=1.13.2 <2.0.0), specifically the Dart-SDK and Dartium (a version of Chromium with native support for Dart through the Dart VM). One of the simplest ways to get both is to install the Dart Editor bundle, which includes the editor, SDK and Dartium. See the Dart tools download page for instructions.
  You can also download both stable and dev channel versions from the download archive. In that case, on Windows, Dart must be added to the Path (e.g. path-to-dart-sdk-folder\bin) and a new DARTIUM_BIN environment variable must be created, pointing to the executable (e.g. path-to-dartium-folder\chrome.exe).

Fork and clone the Angular repository:

1. Login to your GitHub account or create one by following the instructions given here.
2. Fork the main Angular repository.
3. Clone your fork of the Angular repository and define an upstream remote pointing back to the Angular repository that you forked in the first place.

# Clone your GitHub repository:
git clone git@github.com:<github username>/angular.git

# Go to the Angular directory:
cd angular

# Add the main Angular repository as an upstream remote to your repository:
git remote add upstream https://github.com/angular/angular.git

Define the environment variables listed below. These are mainly needed for the testing. The notation shown here is for bash; adapt as appropriate for your favorite shell.

Examples given below of possible values for initializing the environment variables assume Mac OS X and that you have installed the Dart Editor in the directory named by DART_EDITOR_DIR=/Applications/dart. This is only for illustrative purposes.

# DARTIUM_BIN: path to a Dartium browser executable; used by Karma to run Dart tests
export DARTIUM_BIN="$DART_EDITOR_DIR/chromium/Chromium.app/Contents/MacOS/Chromium"

Add the Dart SDK bin directory to your path and/or define DART_SDK (this is also detailed here):

# DART_SDK: path to a Dart SDK directory
export DART_SDK="$DART_EDITOR_DIR/dart-sdk"

# Update PATH to include the Dart SDK bin directory
PATH+=":$DART_SDK/bin"

And specify where the pub’s dependencies are downloaded. By default, this directory is located under .pub_cache in your home directory (on Mac and Linux), or in AppData\Roaming\Pub\Cache (on Windows).

# PUB_CACHE: location of pub dependencies
export PUB_CACHE="/Users/<user>/.pub-cache"

Next, install the JavaScript modules and Dart packages needed to build and test Angular:

# Install Angular project dependencies (package.json)
npm install

Optional: In this document, we make use of project local npm package scripts and binaries (stored under ./node_modules/.bin) by prefixing these command invocations with $(npm bin); in particular gulp and protractor commands. If you prefer, you can drop this path prefix by either:

Option 1: globally installing these two packages as follows:

• npm install -g gulp (you might need to prefix this command with sudo)
• npm install -g protractor (you might need to prefix this command with sudo)

Since global installs can become stale, and required versions can vary by project, we avoid their use in these instructions.

Option 2: defining a bash alias like alias nbin='PATH=$(npm bin):$PATH' as detailed in this Stackoverflow answer and used like this: e.g., nbin gulp build.

To build Angular and prepare tests, run:

$(npm bin)/gulp build

Notes:

• Results are put in the dist folder.
• This will also run pub get for the subfolders in modules and run dartanalyzer for every file that matches <module>/src/<module>.dart, e.g. di/src/di.dart.

You can selectively build either the JS or Dart versions as follows:

• $(npm bin)/gulp build.js
• $(npm bin)/gulp build.dart

To clean out the dist folder, run:

$(npm bin)/gulp clean

• npm test: full test suite for both JS and Dart versions of Angular. These are the same tests that run on Travis.

You can selectively run either the JS or Dart versions as follows:

• $(npm bin)/gulp test.all.js
• $(npm bin)/gulp test.all.dart

You can run just the unit tests as follows:

• $(npm bin)/gulp test.unit.js: JS tests in a browser; runs in watch mode (i.e. watches the test files for changes and re-runs tests when files are updated).
• $(npm bin)/gulp test.unit.cjs: JS tests in NodeJS; runs in watch mode.
• $(npm bin)/gulp test.unit.dart: Dart tests in Dartium; runs in watch mode.

If you prefer running tests in "single-run" mode rather than watch mode use:

• $(npm bin)/gulp test.unit.js/ci
• $(npm bin)/gulp test.unit.cjs/ci
• $(npm bin)/gulp test.unit.dart/ci

The task updates the dist folder with transpiled code whenever a source or test file changes, and Karma is run against the new output.

Note: If you want to only run a single test you can alter the test you wish to run by changing it to iit or describe to ddescribe. This will only run that individual test and make it much easier to debug. xit and xdescribe can also be useful to exclude a test and a group of tests respectively.

Note: watch mode needs symlinks to work, so if you're using windows, ensure you have the rights to built them in your operating system.

First, in a terminal, create a tunnel with Sauce Connect or Browser Stack Local, and valid credentials.

Then, in another terminal:

• Define the credentials as environment variables, e.g.:

export SAUCE_USERNAME='my_user'; export SAUCE_ACCESS_KEY='my_key';
export BROWSER_STACK_USERNAME='my_user'; export BROWSER_STACK_ACCESS_KEY='my_key';

• Then run gulp test.unit.js.(sauce|browserstack) --browsers=option1,option2,..,optionN
  The options are any mix of browsers and aliases which are defined in the browser-providers.conf.js file.
  They are case insensitive, and the SL_ or BS_ prefix must not be added for browsers.

Some examples of commands:

gulp test.unit.js.sauce --browsers=Safari8,ie11  //run in Sauce Labs with Safari 8 and IE11
gulp test.unit.js.browserstack --browsers=Safari,IE  //run in Browser Stack with Safari 7, Safari 8, Safari 9, IE 9, IE 10 and IE 11
gulp test.unit.js.sauce --browsers=IOS,safari8,android5.1  //run in Sauce Labs with iOS 7, iOS 8, iOs 9, Safari 8 and Android 5.1

1. $(npm bin)/gulp build.js.cjs (builds benchpress and tests into dist/js/cjs folder).
2. $(npm bin)/gulp serve.js.prod serve.dart (runs a local webserver).
3. $(npm bin)/protractor protractor-js.conf.js: JS e2e tests.
4. $(npm bin)/protractor protractor-dart2js.conf.js: dart2js e2e tests.

Angular specific command line options when running protractor:

• $(npm bin)/protractor protractor-{js|dart2js}-conf.js --ng-help

1. $(npm bin)/gulp build.js.cjs (builds benchpress and tests into dist/js/cjs folder)
2. $(npm bin)/gulp serve.js.prod serve.dart (runs a local webserver)
3. $(npm bin)/protractor protractor-js.conf.js --benchmark: JS performance tests
4. $(npm bin)/protractor protractor-dart2js.conf.js --benchmark: dart2js performance tests

Angular specific command line options when running protractor (e.g. force gc, ...): $(npm bin)/protractor protractor-{js|dart2js}-conf.js --ng-help

We use clang-format to automatically enforce code style for our TypeScript code. This allows us to focus our code reviews more on the content, and less on style nit-picking. It also lets us encode our style guide in the .clang-format file in the repository, allowing many tools and editors to share our settings.

To check the formatting of your code, run

gulp check-format

Note that the continuous build on Travis runs gulp enforce-format. Unlike the check-format task, this will actually fail the build if files aren't formatted according to the style guide.

Your life will be easier if you include the formatter in your standard workflow. Otherwise, you'll likely forget to check the formatting, and waste time waiting for a build on Travis that fails due to some whitespace difference.

• Use $(npm bin)/clang-format -i [file name] to format a file (or multiple).
• Use gulp enforce-format to check if your code is clang-format clean. This also gives you a command line to format your code.
• clang-format also includes a git hook, run git clang-format to format all files you touched.
• You can run this as a git pre-commit hook to automatically format your delta regions when you commit a change. In the angular repo, run

    $ echo -e '#!/bin/sh\nexec git clang-format' > .git/hooks/pre-commit
    $ chmod u+x !$

• WebStorm can run clang-format on the current file.
  1. Under Preferences, open Tools > External Tools.
  2. Plus icon to Create Tool
  3. Fill in the form:
  • Name: clang-format
  • Description: Format
  • Synchronize files after execution: checked
  • Open console: not checked
  • Show in: Editor menu
  • Program: $ProjectFileDir$/node_modules/.bin/clang-format
  • Parameters: -i -style=file $FilePath$
  • Working directory: $ProjectFileDir$
• clang-format integrations are also available for many popular editors (vim, emacs, Sublime Text, etc.).

We use tslint for linting. See linting rules in gulpfile. To lint, run

$ gulp lint

The following gulp task will generate the API docs in the dist/angular.io/partials/api/angular2:

$(npm bin)/gulp docs/angular.io

You can serve the generated documentation to check how it would render on angular.io:

• check out the angular.io repo locally,
• install dependencies as described in the angular.io README,
• copy the generated documentation from your local angular repo at angular/dist/angular.io/partials/api/angular2 to your local angular.io repo at angular.io/public/docs/js/latest/api,
• run harp compile at the root of the angular.io repo to check the generated documentation for errors,
• run harp server and open a browser at http://localhost:9000/docs/js/latest/api/ to check the rendered documentation.

• modules/*: modules that will be loaded in the browser
• tools/*: tools that are needed to build Angular
• dist/*: build files are placed here.

• *.ts: TypeScript files that get transpiled to Dart and EcmaScript 5/6
• *.dart: Dart files that don't get transpiled

For instructions on setting up Continuous Integration using Travis, see the instructions given here.

See the wiki.

If you need to debug the transpiler:

• add a debugger; statement in the transpiler code,
• from the root folder, execute node debug $(npm bin)/gulp build to enter the node debugger
• press "c" to execute the program until you reach the debugger; statement,
• you can then type "repl" to enter the REPL and inspect variables in the context.

See the Node.js manual for more information.

Notes:

• You can also execute node $(npm bin)/karma start karma-dart.conf.js depending on which code you want to debug (the former will process the "modules" folder while the later processes the transpiler specs).
• You can also add debugger; statements in the specs (JavaScript). The execution will halt when the developer tools are opened in the browser running Karma.

If you need to debug the tests:

• add a debugger; statement to the test you want to debug (or the source code),
• execute karma $(npm bin)/gulp test.js,
• press the top right "DEBUG" button,
• open the DevTools and press F5,
• the execution halts at the debugger; statement

Note (WebStorm users):

1. Create a Karma run config from WebStorm.
2. Then in the "Run" menu, press "Debug 'karma-js.conf.js'", and WebStorm will stop in the generated code on the debugger; statement.
3. You can then step into the code and add watches.

The debugger; statement is needed because WebStorm will stop in a transpiled file. Breakpoints in the original source files are not supported at the moment.