angular-cn/DEVELOPER.md

# 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](https://github.com/angular/angular/blob/master/CONTRIBUTING.md)
for how to contribute your own code to

1. [Prerequisite Software](#prerequisite-software)
2. [Getting the Sources](#getting-the-sources)
3. [Environment Variable Setup](#environment-variable-setup)
4. [Installing NPM Modules and Dart Packages](#installing-npm-modules-and-dart-packages)
5. [Running Tests Locally](#running-tests-locally)
6. [Project Information](#project-information)
7. [CI using Travis](#ci-using-travis)
8. [Debugging](#debugging)

## Prerequisite Software

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

* [Dart](https://www.dartlang.org) (version `>=1.9.0-dev.8.0`), specifically the Dart-SDK and
  Dartium (a version of [Chromium](http://www.chromium.org) 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](https://www.dartlang.org/tools)
  download [page for instructions](https://www.dartlang.org/tools/download.html); note that you can
  download both **stable** and **dev** channel versions from the [download
  archive](https://www.dartlang.org/tools/download-archive).

* [Git](http://git-scm.com) and/or the **Github app** (for [Mac](http://mac.github.com) or
  [Windows](http://windows.github.com)): the [Github Guide to Installing
  Git](https://help.github.com/articles/set-up-git) is a good source of information.

* [Node.js](http://nodejs.org) 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](https://www.google.com/chrome/browser/canary.html), 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](https://github.com/signup/free).
2. [Fork](http://help.github.com/forking) the [main Angular
   repository](https://github.com/angular/angular).
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:

```shell
# 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`](http://www.gnu.org/software/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.

```shell
# 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](https://www.dartlang.org/tools/pub/installing.html)):

```shell
# 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:

```shell
# 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

```shell
$(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:
```shell
$(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](https://github.com/angular/angular.dart/blob/master/travis.md).

## 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](http://nodejs.org/api/debugger.html) 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.