babel-codemod

babel-codemod

babel-codemod rewrites JavaScript using babel plugins.

Install

Install from yarn:

$ yarn global add babel-codemod

NOTE: You can also install using npm install -g babel-codemod.

This will install the runner as codemod. This package requires node v6 or higher.

Usage

The primary interface is as a command line tool, usually run like so:

$ codemod --plugin transform-module-name \
  path/to/file.js \
  another/file.js

This will re-write the files path/to/file.js and another/file.js by transforming them with the babel plugin transform-module-name. Multiple plugins may be specified, and multiple file or directories may be re-written at once.

For more detailed options, run codemod --help.

Writing a Plugin

There are many, many existing plugins that you can use. However, if you need to write your own you should consult the babel handbook. If you publish a plugin intended specifically as a codemod, consider using both the babel-plugin and babel-codemod keywords.

Transpiling using babel plugins

babel-codemod also supports non-standard/future language features that are not currently supported by the latest version of node. It does this by leveraging babel-preset-env which loads the latest babel plugins. This feature is on by default.

This feature should support most use cases when writing plugins in advanced JavaScript syntax. However, if you are writing plugins with syntax that is beyond "latest", or you would like to use your own set of plugins and presets, you can pass in the --find-babel-config switch in combination with a local .babelrc file that lists the presets/plugins you want applied to your plugin code.

# Run a local plugin that is passed through locally installed babel plugins
$ codemod --find-babel-config --plugin ./my-plugin.js src/

This requires that all babel plugins and presets be installed locally and are listed in your .babelrc file. babel-codemod uses babel-register under the hood too accomplish this and all .babelrc lookup rules apply.

Transpiling using TypeScript

There is currently an open issue for supporting plugins written in typescript. In the interim, you can take the same approach using --require along with ts-node/register.

For example:

# Run a local plugin written with TypeScript.
$ codemod --require ts-node/register --plugin ./my-plugin.ts src/

Contributing

See CONTRIBUTING.md for information on setting up the project for development and on contributing to the project.

Status

License

Copyright 2017 Square, Inc.

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.