Files
KaTeX/CONTRIBUTING.md
ylemkimon 5f32b71c85 Use webpack to build files and webpack-dev-server for testing (#1068)
* Create a separate entry point for webpack

Created a webpack entry point for KaTeX, which imports katex.less. As
flow[1] and jest[2] doesn't support CSS modules natively, a separate
entry point is used and it is not flowtyped.

[1] https://gist.github.com/lambdahands/d19e0da96285b749f0ef
[2] https://facebook.github.io/jest/docs/en/webpack.html

* Use webpack to build files

* Made webpack.config.js export valid webpack configuration
* Use:
browserify -> webpack
babelify -> babel-loader
UglifyJS CLI -> UglifyJsPlugin
Less CLI -> less-loader
cleancss -> cssnano in css-loader
build/fonts -> file-loader
* Inline CSS(Less) using style-loader and export them using
ExtractTextPlugin
* Add `watch` npm script calling `webpack --watch`

* Improve local testing(webpack-dev-server)

* Made webpackDevServer export a valid webpack configuration
* Compile Less and inline CSS using less-loader and style-loader
* Instead of copying files serve files from /static and use file-loader
* Remove old server.js and its dependencies

* Use webpack-dev-server in Screenshotter

* Include contrib in webpack-dev-server

+ Moved common configurations to webpack.common.js

* Rename webpackDevServer.js to webpack.dev...

to be consistent, avoid confusion with webpack-dev-server and follow
webpack configuration naming convention.

* Remove unnecessary conditional output.path

* Use map instead of reduce

+ Add comments regarding function arguments

* Remove unnecessary mkdir and clean build/* before build

* Use katex as external dependency instead of global variable in contrib

Fixes #692.

* Unblock codes as they are built as a module

* Update package-lock.json

* Add comments regarding devServer option

* Lint renamed webpack.dev.js

a0d8b33

* Export ES6 module and expose its default export

* Revert "Browserify hotfix (#1057)"

This reverts commit f6b509123b.

* Enables colors on the console when running the dev server in Screenshotter

* Add context to webpack configuration

Allows webpack to be run from other directories

* Move `rm -rf build/*` to npm scripts

* Check dependencies before build

* Move UglifyJsPlugin into config creation

* Let webpack handle ES6 modules

Do not transform modules to commonjs in Babel. However Jest doesn't not
support ES6 modules, so transfrom modules to commonjs when NODE_ENV is
`test`.

* Add documentation on testing in IE 9 and 10 using webpack-dev-server

Changed version range to include IE-compatible version
2018-01-21 19:48:25 -05:00

7.8 KiB

Contributing to KaTeX

We welcome pull requests to KaTeX. If you'd like to add a new symbol, or try to tackle adding a larger feature, keep reading. If you have any questions, or want help solving a problem, feel free to stop by our gitter channel.

Helpful contributions

If you'd like to contribute, try contributing new symbols or functions that KaTeX doesn't currently support. The wiki has a page which lists all of the supported functions as well as a page that describes how to examine TeX commands and where to find rules which can be quite useful when adding new commands. There's also a user-contributed preview page showing how KaTeX would render a series of symbols/functions (including the ones MathJax listed in their documentation and the extra ones supported by KaTeX). You can check them to see if we don't support a function you like, or try your function in the interactive demo at http://khan.github.io/KaTeX/.

Single symbols

There are many individual symbols that KaTeX doesn't yet support. Read through the symbols.js file for more information on how to add a symbol.

To figure out the unicode symbol for the symbol you are trying to add, try using the symbol in MathJax to see what unicode symbol it outputs. An interactive MathJax shell can be found here.

To figure out what group your symbol falls into, look through the symbols list to find other symbols of a similar kind. (e.g. if you were adding \neq, look for =). If you cannot find anything similar, or are unsure, you can try using your symbol in TeX surrounded by other different kinds of symbols, and seeing whether your spacing matches the spacing that TeX produces.

Once your symbol works, check the JavaScript console to make sure you don't get a message like "Can't find character metrics for _" when you render your symbol. If you do, check out extract_ttfs.py.

Adding new functions

New functions should be added in src/functions using defineFunction from defineFunction.js. Read the comments in this file to get started. Look at phantom.js and delimsizing.js as examples of how to use defineFunction. Notice how delimsizing.js groups several related functions together in a single call to defineFunction.

The new method of defining functions combines methods that were previously spread out over three different files functions.js, buildHTML.js, buildMathML.js into a single file. The goal is to have all functions use this new system.

Testing

Local testing can be done by running the webpack-dev-server using configuration webpack.dev.js. Run npm install to install dependencies, and then npm start to start the server.

This will host an interactive editor at http://localhost:7936/ to play around with and test changes.

webpack-dev-server 2.8.0 introduced a change which included ES6 keywords const and let within the scripts being served to the browser, and therefore doesn't support IE 9 and 10. If you want to test in IE 9 and 10, install version 2.7.1 by running npm install webpack-dev-server@2.7.1.

Jest tests

The JavaScript parser and some of the HTML and MathML tree builders are tested with Jest. These tests can be run using node with npm run jest. If you need to debug the tests see https://facebook.github.io/jest/docs/troubleshooting.html

The interactive editor can also be used for debugging tests in the browser by copy/pasting the test case to be debugged into the editor. The permalink option can come in really useful when doing repeated runs of the same test case.

The Jest tests should be run after every change, even the addition of small symbols. However, Travis will run these tests when you submit a pull request, in case you forget.

If you make any changes to Parser.js, add Jest tests to ensure they work.

Screenshot tests

To ensure the final output looks good, we screenshot different expressions. These tests can be run by using the Screenshotter docker.

The screenshot tests should be run if you add anything more significant than individual symbols. These tests are not automatically run, so please remember! If the new images are different (meaning they are not byte-by-byte the same as the old ones), inspect them visually. If there are no visible changes, that is okay. If things change in a way consistent with your additions, explain what changed and why. Otherwise, figure out what is causing the changes and fix it!

If you add a feature that is dependent on the final output looking the way you created it, add a screenshot test. See ss_data.yaml.

You can use our texcmp tool to compare the outputs of a screenshot test as generated by KaTeX and LaTeX. It's often useful to attach the resulting "visual diff" to your pull request with a new feature.

Testing in other browsers

KaTeX supports all major browsers, including IE 9 and newer. Unfortunately, it is hard to test new changes in many browsers. If you can, please test your changes in as many browsers as possible. In particular, if you make CSS changes, try to test in IE 9, using modern.ie VMs.

Style guide

Code

  • 4 spaces for indentation
  • 80 character line length
  • commas last
  • declare variables in the outermost scope that they are used
  • camelCase for variables in JavaScript
  • snake_case for variables in Python

In general, try to make your code blend in with the surrounding code.

Pull Requests

  • link back to the original issue(s) whenever possible
  • new commands should be added to the wiki
  • commits should be squashed before merging
  • large pull requests should be broken into separate pull requests (or multiple logically cohesive commits), if possible

Working with submodules

The fonts for KaTeX live in a submodule which appears in submodules/katex-fonts. Most of the time you won't have to worry about this unless you're making changes to fonts or switching between branches where submodules/katex0fonts point to different commits.

If you're not familiar with submodule, it's probably easiest to get started by adding the following aliases to your .gitconfig:

[alias]
  # Versions of commands that handle submodules properly.
  co = "!f() { git checkout \"$@\" && git submodule update --init --recursive; }; f"
  p = "!f() { git pull \"$@\" && git submodule update --init --recursive; }; f"
  m = "!f() { git merge \"$@\" && git submodule update --init --recursive; }; f"
  gsu = "!f() { git submodule sync --recursive && git submodule update --init --recursive; }; f"

git co, git p, and git m work just like git checkout, git pull, and git merge respectively but automatically update submodules. For more info about how to use git submodules see https://chrisjean.com/git-submodules-adding-using-removing-and-updating/.

When submitting pull requests, that update katex-fonts, you'll need to submit two pull requests: one for KaTeX/katex-fonts and one for Khan/KaTeX.

CLA

In order to contribute to KaTeX, you must first sign the CLA, found at www.khanacademy.org/r/cla

License

KaTeX is licenced under the MIT License.