angular-cn/DEVELOPER.md

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Building and Testing Angular 2 for JS and Dart

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.

See the contributing guidelines for how to contribute your own code to

  1. Prerequisite Software
  2. Getting the Sources
  3. Environment Variable Setup
  4. Installing NPM Modules and Dart Packages
  5. Running Tests Locally
  6. Project Information
  7. CI using Travis
  8. Debugging

Prerequisite Software

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

  • Dart (version >=1.9.0-dev.8.0), 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; note that you can download both stable and dev channel versions from the download archive.

  • Git and/or the Github app (for Mac or Windows): the Github Guide to Installing Git is a good source of information.

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

  • Chrome Canary, a version of Chrome with bleeding edge functionality, built especially for developers (and early adopters).

Getting the Sources

Forking and cloning 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

Environment Variable Setup

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"

Installing NPM Modules and Dart Packages

Next, install the modules and packages needed to build Angular and run tests:

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

# Ensure protractor has the latest webdriver
$(npm bin)/webdriver-manager update

# Install Dart packages
pub 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 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, we avoid their use in these instructions.

Build commands

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

To clean out the dist folder use:

$(npm bin)/gulp clean

Running Tests Locally

Basic tests

  1. $(npm bin)/gulp test.unit.js: JS tests in a browser; runs in watch mode (i.e. karma watches the test files for changes and re-runs tests when files are updated).
  2. $(npm bin)/gulp test.unit.cjs: JS tests in NodeJS (requires a build before)
  3. $(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.dart/ci

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 for transpiler tests: The karma preprocessor is setup in a way so that after every test run the transpiler is reloaded. With that it is possible to make changes to the preprocessor and run the tests without exiting karma (just touch a test file that you would like to run).

E2e tests

  1. $(npm bin)/gulp build.js.cjs (builds benchpress and tests into dist/js/cjs folder).
  2. $(npm bin)/gulp serve.js.prod serve.js.dart2js (runs 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

Performance tests

  1. $(npm bin)/gulp build.js.cjs (builds benchpress and tests into dist/js/cjs folder)
  2. $(npm bin)/gulp serve.js.prod serve.js.dart2js (runs 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

Project Information

Folder structure

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

File endings

  • *.js: javascript files that get transpiled to Dart and EcmaScript 5
  • *.es6: javascript files that get transpiled only to EcmaScript 5
  • *.es5: javascript files that don't get transpiled
  • *.dart: dart files that don't get transpiled

CI using Travis

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

Debugging

Debug the transpiler

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.

Debug the tests

If you need to debug the tests:

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

Note (WebStorm users): You can create a Karma run config from WebStorm. Then in the "Run" menu, press "Debug 'karma-js.conf.js'", WebStorm will stop in the generated code on the debugger; statement. 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.