Yoga builds with buck. Make sure you install buck before contributing to Yoga. Yoga's main implementation is in C++, with bindings to supported languages and frameworks. When making changes to Yoga please ensure the changes are also propagated to these bindings when applicable.

Alternatively, you can build and install Yoga using vcpkg dependency manager:

git clone https://github.com/Microsoft/vcpkg.git
cd vcpkg
./bootstrap-vcpkg.sh
./vcpkg integrate install
./vcpkg install yoga

The Yoga port in vcpkg is kept up to date by Microsoft team members and community contributors.

If the version is out of date, please create an issue or pull request on the vcpkg repository.

For testing we rely on gtest as a submodule. After cloning Yoga run git submodule init followed by git submodule update.

For any changes you make you should ensure that all the tests are passing. In case you make any fixes or additions to the library please also add tests for that change to ensure we don't break anything in the future. Tests are located in the tests directory. Run the tests by executing buck test //:yoga.

Instead of manually writing a test which ensures parity with web implementations of Flexbox you can run gentest/gentest.rb to generate a test for you. You can write html which you want to verify in Yoga, in gentest/fixtures folder, such as the following.

<div id="my_test" style="width: 100px; height: 100px; align-items: center;">
  <div style="width: 50px; height: 50px;"></div>
</div>

Run gentest/gentest.rb to generate test code and re-run buck test //:yoga to validate the behavior. One test case will be generated for every root div in the input html.

You should run bundle install in the gentest directory to install dependencies for the gentest/gentest.rb Ruby script.

.NET testing is not integrated in buck yet, you might need to set up .NET testing environment. We have a script which to launch C# test on macOS, csharp/tests/Facebook.Yoga/test_macos.sh.

Benchmarks are located in benchmark/YGBenchmark.c and can be run with buck run //benchmark:benchmark. If you think your change has affected performance please run this before and after your change to validate that nothing has regressed. Benchmarks are run on every commit in CI.

Installing through NPM

npm install yoga-layout

By default this will install the library and try to build for all platforms (node, browser asm, and standalone webpack). You may receive errors if you do not have the required platform development tools already installed. To preset the platform you'd like to build for you can set a .npmrc property first.

npm config set yoga-layout:platform standalone

This will now only run the standalone webpack build upon install.

To publish a new release, follow these steps:

1. Ensure you have your GPG key set up and your OSS Sonatype credentials handy.
2. Add the follow entries to either your local gradle.properties (don't forget to revert) or your global ~/.gradle/gradle.properties:

# You get these from https://oss.sonatype.org/#profile;User%20Token
mavenCentralRepositoryUsername=<username>
mavenCentralRepositoryPassword=<password>

# You can get the keyId (in GPG 1.4 format) by running `gpg1 --list-keys`.
signing.secretKeyRingFile=</path/to/secring.gpg>
signing.keyId=<key_id>
signing.password=<key_password>

3. Change the VERSION_NAME in gradle.properties to a non-SNAPSHOT release.
4. Commit and land the version change.
5. Run ./gradlew publishToMaven.
6. Run ./gradlew closeAndReleaseRepository.
7. Change the VERSION_NAME in gradle.properties back to a new SNAPSHOT release.
8. Commit and land the version change.
9. Celebrate! You've made a release!