This document describes how to set up your development environment to build and test Angular.
It also explains the basic mechanics of using git
, node
, and yarn
.
- Prerequisite Software
- Getting the Sources
- Installing NPM Modules
- Building
- Running Tests Locally
- Formatting your Source Code
- Linting/verifying your Source Code
- Publishing Snapshot Builds
- Bazel Support
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 and Windows); GitHub's Guide to Installing Git is a good source of information.
-
Node.js, (version specified in the engines field of
package.json
) which is used to run a development web server, run tests, and generate distributable files. -
Yarn (version specified in the engines field of
package.json
) which is used to install dependencies. -
Optional: Java version 7 or higher as required by Closure Compiler. Most developers will not need this. Java is required for running some of the integration tests.
Fork and clone the Angular repository:
- Login to your GitHub account or create one by following the instructions given here.
- Fork the main Angular repository.
- 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 [email protected]:<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
Next, install the JavaScript modules needed to build and test Angular:
# Install Angular project dependencies (package.json)
yarn install
To build Angular run:
node ./scripts/build/build-packages-dist.js
- Results are put in the
dist/packages-dist
folder.
Bazel is used as the primary tool for building and testing Angular. Building and testing are incremental with Bazel, and it's possible to only run tests for an individual package instead of for all packages. Read more about this in the BAZEL.md document.
You should execute all test suites before submitting a PR to GitHub. Note that not all tests support both Ivy and View Engine, so they need to be run separately:
yarn test-ivy-aot //packages/...
yarn test-non-ivy //packages/...
Note: The first test run will be much slower than future runs. This is because future runs will benefit from Bazel's capability to do incremental builds.
All the tests are executed on our Continuous Integration infrastructure. PRs can only be merged if the code is formatted properly and all tests are passing.
Often for developers the best way to ensure the changes they have made work as expected is to run
use changes in another library or project. To do this developers can build Angular locally, and
using yarn link
build a local project with the created artifacts.
This can be done by running:
yarn ng-dev build-and-link <path-to-local-project-root>
Angular uses clang-format to format the source code. If the source code is not properly formatted, the CI will fail and the PR cannot be merged.
You can automatically format your code by running:
yarn ng-dev format changed [shaOrRef]
: format only files changed since the provided sha/ref.shaOrRef
defaults tomaster
.yarn ng-dev format all
: format all source codeyarn ng-dev format files <files..>
: format only provided files
A better way is to set up your IDE to format the changed file on each file save.
- Install Clang-Format extension for VS Code.
- It will automatically pick up the settings from
.vscode/settings.json
. If you haven't already, create asettings.json
file by following the instructions here.
- Install the ClangFormatIJ plugin
- Open
Preferences->Tools->clang-format
- Find the field named "PATH"
- Add
<PATH_TO_YOUR_WORKSPACE>/angular/node_modules/clang-format/bin/<OS>/
where the OS options are:darwin_x64
,linux_x64
, andwin32
.
- Install Vim Clang-Format.
- Create a project-specific
.vimrc
in your Angular directory containing
let g:clang_format#command = '$ANGULAR_PATH/node_modules/.bin/clang-format'
where $ANGULAR_PATH
is an environment variable of the absolute path of your Angular directory.
You can check that your code is properly formatted and adheres to coding style by running:
$ yarn lint
When a build of any branch on the upstream fork angular/angular is green on CircleCI, it
automatically publishes build artifacts to repositories in the Angular org, eg. the @angular/core
package is published to https://github.com/angular/core-builds.
You may find that your un-merged change needs some validation from external participants. Rather than requiring them to pull your Pull Request and build Angular locally, they can depend on snapshots of the Angular packages created based on the code in the Pull Request.
Each CI run for a Pull Request stores the built Angular packages as build artifacts. The artifacts are not guaranteed to be available as a long-term distribution mechanism, but they are guaranteed to be available around the time of the build.
You can access the artifacts for a specific CI run by going to the workflow page, clicking on the
publish_packages_as_artifacts
job and then switching to the "ARTIFACTS" tab.
On the "Artifacts" tab, there is a list of links to compressed archives for Angular packages. The
archive names are of the format <package-name>-pr<pr-number>-<sha>.tgz
(for example
core-pr12345-a1b2c3d.tgz
).
One can use the URL to the .tgz
file for each package to install them as dependencies in a
project they need to test the Pull Request changes against. Both
npm and yarn
support installing dependencies from URLs to .tgz
files, for example by updating the dependencies
in package.json
to point to the artifact URLs and then running npm/yarn install
:
"dependencies": {
"@angular/common": "https://<...>.circle-artifacts.com/0/angular/common-pr12345-a1b2c3d.tgz",
"@angular/core": "https://<...>.circle-artifacts.com/0/angular/core-pr12345-a1b2c3d.tgz",
"...": "..."
}
In addition to the individual package archives, a .tgz
file including all packages is also
available (named all-pr<pr-number>-<sha>.tgz
). This can be used if one prefers to download all
packages locally and test them by either of the following ways:
-
Update the dependencies in
package.json
to point to the local uncompressed package directories. -
Directly copy the local uncompressed package directories into the
node_modules/
directory of a project.
Note that (while faster) the second approach has limitations. For example:
a. Any transitive dependencies of the copied packages will not be automatically updated.
b. The packages need to be copied over every time npm/yarn install
is run.
c. Some package managers (such as pnpm
or yarn pnp
) might not work correctly.
You can also manually publish *-builds
snapshots just like our CircleCI build does for upstream
builds. Before being able to publish the packages, you need to build them locally by running the
./scripts/build/build-packages-dist.js
script.
First time, you need to create the GitHub repositories:
$ export TOKEN=[get one from https://github.com/settings/tokens]
$ CREATE_REPOS=1 ./scripts/ci/publish-build-artifacts.sh [GitHub username]
For subsequent snapshots, just run:
$ ./scripts/ci/publish-build-artifacts.sh [GitHub username]
The script will publish the build snapshot to a branch with the same name as your current branch, and create it if it doesn't exist.
- Install Bazel extension for VS Code.
- Install the Bazel plugin
- You can find the settings under
Preferences->Other Settings->Bazel Settings
It will automatically recognize *.bazel
and *.bzl
files.
Bazel builds in the Angular repository use a shared cache. When a build occurs a hash of the inputs is computed and checked against available outputs in the shared cache. If an output is found, it is used as the output for the build action rather than performing the build locally.
Remote Build Execution requires authentication as a google.com or angular.io account.
The --config=remote
flag can be added to enable remote execution of builds. This flag can be added to
the .bazelrc.user
file using the script at scripts/local-dev/setup-rbe.sh
.