Chai Contribution Guidelines

We like to encourage you to contribute to the Chai.js repository. This should be as easy as possible for you but there are a few things to consider when contributing. The following guidelines for contribution should be followed if you want to submit a pull request or open an issue.

Following these guidelines helps to communicate that you respect the time of the developers managing and developing this open source project. In return, they should reciprocate that respect in addressing your issue or assessing patches and features.

Table of Contents


  • Creating an Issue or Pull Request requires a GitHub account.
  • Issue reports should be clear, concise and reproducible. Check to see if your issue has already been resolved in the master branch or already reported in Chai's GitHub Issue Tracker.
  • Pull Requests must adhere to strict coding style guidelines.
  • In general, avoid submitting PRs for new Assertions without asking core contributors first. More than likely it would be better implemented as a plugin.
  • Additional support is available via the Google Group or on
  • IMPORTANT: By submitting a patch, you agree to allow the project owner to license your work under the same license as that used by the project.


The issue tracker is the preferred channel for bug reports, feature requests and submitting pull requests, but please respect the following restrictions:

  • Please do not use the issue tracker for personal support requests (use Google Group or IRC).
  • Please do not derail or troll issues. Keep the discussion on topic and respect the opinions of others

Bug Reports

A bug is a demonstrable problem that is caused by the code in the repository.

Guidelines for bug reports:

  1. Use the GitHub issue search — check if the issue has already been reported.
  2. Check if the issue has been fixed — try to reproduce it using the latest master or development branch in the repository.
  3. Isolate the problem — create a test case to demonstrate your issue. Provide either a repo, gist, or code sample to demonstrate you problem.

A good bug report shouldn't leave others needing to chase you up for more information. Please try to be as detailed as possible in your report. What is your environment? What steps will reproduce the issue? What browser(s) and/or Node.js versions experience the problem? What would you expect to be the outcome? All these details will help people to fix any potential bugs.


Short and descriptive example bug report title

A summary of the issue and the browser/OS environment in which it occurs. If suitable, include the steps required to reproduce the bug.

  1. This is the first step
  2. This is the second step
  3. Further steps, etc.

<url> - a link to the reduced test case OR

// code sample

Any other information you want to share that is relevant to the issue being reported. This might include the lines of code that you have identified as causing the bug, and potential solutions (and your opinions on their merits).

Feature Requests

Feature requests are welcome. But take a moment to find out whether your idea fits with the scope and aims of the project. It‘s up to you to make a strong case to convince the project’s developers of the merits of this feature. Please provide as much detail and context as possible.

Furthermore, since Chai.js has a robust plugin API, we encourage you to publish new Assertions as plugins. If your feature is an enhancement to an existing Assertion, please propose your changes as an issue prior to opening a pull request. If the core Chai.js contributors feel your plugin would be better suited as a core assertion, they will invite you to open a PR in chaijs/chai.

Pull Requests

  • PRs for new core-assertions are advised against.
  • PRs for core-assertion bug fixes are always welcome.
  • PRs for enhancing the interfaces are always welcome.
  • PRs that increase test coverage are always welcome.
  • PRs are scrutinized for coding-style.

Good pull requests - patches, improvements, new features - are a fantastic help. They should remain focused in scope and avoid containing unrelated commits.

Please ask first before embarking on any significant pull request (e.g. implementing features, refactoring code), otherwise you risk spending a lot of time working on something that the project's developers might not want to merge into the project.

Please adhere to the coding conventions used throughout a project (indentation, accurate comments, etc.) and any other requirements (such as test coverage). Please review the Chai.js Coding Style Guide.

Follow this process if you'd like your work considered for inclusion in the project:

  1. Fork the project, clone your fork, and configure the remotes:
# Clone your fork of the repo into the current directory
git clone<your-username>/<repo-name>
# Navigate to the newly cloned directory
cd <repo-name>
# Assign the original repo to a remote called "upstream"
git remote add upstream<upstream-owner>/<repo-name>
  1. If you cloned a while ago, get the latest changes from upstream:
git checkout <dev-branch>
git pull upstream <dev-branch>
  1. Create a new topic branch (off the main project development branch) to contain your feature, change, or fix:
git checkout -b <topic-branch-name>
  1. Commit your changes in logical chunks. Use Git's interactive rebase feature to tidy up your commits before making them public.

  2. Locally merge (or rebase) the upstream development branch into your topic branch:

git pull [--rebase] upstream <dev-branch>
  1. Push your topic branch up to your fork:
git push origin <topic-branch-name>
  1. Open a Pull Request with a clear title and description.

IMPORTANT: By submitting a patch, you agree to allow the project owner to license your work under the same license as that used by the project.



For most of the documentation you are going to want to visit

Alternatively, the wiki might be what you are looking for.

Or finally, you may find a core-contributor or like-minded developer in any of our support channels.

Core Contributors

Feel free to reach out to any of the core-contributors with you questions or concerns. We will do our best to respond in a timely manner.