# NOTE: DO NOT OPEN ISSUES FOR QUESTIONS AND SUPPORT. SEE THE README FOR MORE INFO.

----

<p align="center">
   <strong><a href="#setup">Setup</a></strong>
   |
   <strong><a href="#running-tests">Running tests</a></strong>
   |
   <strong><a href="#internals">Internals</a></strong>
</p>

----

# Contributing

Contributions are always welcome, no matter how large or small. Before
contributing, please read the
[code of conduct](https://github.com/babel/babel/blob/master/CODE_OF_CONDUCT.md).

## Developing

**Note:** Versions `< 5.1.10` can't be built.

#### Setup

```sh
$ git clone https://github.com/babel/babel
$ cd babel
$ make bootstrap
```

Then you can either run:

```sh
$ make build
```

to build Babel **once** or:

```sh
$ make watch
```

to have Babel build itself then incrementally build files on change.

If you wish to build a copy of Babel for distribution then run:

```sh
$ make build-dist
```

and access the files from `packages/babel-core/dist`.

#### Running tests

You can run tests for all packages via:

```sh
$ make test
```

This is mostly overkill and you can limit the package to a select by using the `TEST_ONLY` environment variable:

```sh
$ TEST_ONLY=babel-cli make test
```

Use the `TEST_GREP` variable to run a subset of tests by name:

```sh
$ TEST_GREP=transformation make test
```

To test the code coverage, use:

```sh
$ make test-cov
```

#### Writing tests

When writing tests in `babylon`, you can easily generate an `expected.json` automatically by just providing the `actual.js` and running `make test-only` like normal.

```js
// Example
- babylon
  - test
    - fixtures
      - comments
        - basic
          - block-trailing-comment
            - actual.js
            - expected.json (will be generated if not created)
```


#### Internals

Please see [`/doc`](/doc) for internals documentation relevant to developing babel.