CONTRIBUTING.md

Contributing to Prettier for PHP

To get up and running, install the dependencies and run the tests:

yarn
yarn test

# format a single file
yarn prettier path/to/file.php`

# run a single test
yarn test tests/{folder of your choice}

Here's what you need to know about the tests:

• The tests use Jest snapshots.
• You can make changes and run jest -u (or yarn test -u) to update the snapshots. Then run git diff to take a look at what changed. Always update the snapshots when opening a PR.
• You can run AST_COMPARE=1 yarn test for a more robust test run. That formats each file, re-parses it, and compares the new AST with the original one and makes sure they are semantically equivalent.

Run yarn lint --fix to automatically format files.

If you can, take look at commands.md and check out Wadler's paper to understand how Prettier works.

Debugging

VScode

Add the following configuration to .vscode/launch.json:

{
    "type": "node",
    "request": "launch",
    "name": "Prettify test.php",
    "skipFiles": [
        "<node_internals>/**"
    ],
    "program": "${workspaceRoot}/node_modules/.bin/prettier",
    "args": ["--plugin=.", "--parser=php", "test.php"],
    "cwd": "${workspaceRoot}",
    "outputCapture": "std"
}

Afterwards, paste some PHP code into test.php, add a breakpoint, and start the debugger.

Browser

node --inspect-brk node_modules/.bin/jest --runInBand tests/{folder of your choice}/`

Details about debugging in the Browser can be found in the Jest troubleshooting docs.