babel-plugin-react-transform
:rocket: Now with Babel 6 support (thank you @thejameskyle!)
This plugin wraps React components with arbitrary transforms. In other words, it allows you to instrument React components in any way—limited only by your imagination.
Ecosystem
For a reference implementation, see react-transform-boilerplate.
Transforms
Feeling inspired? Learn how to write transforms and send a PR!
Demo Project
Check out react-transform-boilerplate for a demo showing a combination of transforms.
Installation
This plugin is designed to be used with the Babel 6 ecosystem. These instructions assume you have a working project set up. If you do not have Babel set up in your project, learn how to integrate it with your toolkit before installing this plugin.
Using NPM
Install plugin and save in devDependencies
:
npm install --save-dev babel-plugin-react-transform
Install some transforms:
npm install --save-dev react-transform-hmr
npm install --save-dev react-transform-catch-errors
Configuration
Add react-transform to the list of plugins in your babel configuration (usually .babelrc
):
{
"presets": ["react", "es2015"],
"env": {
"development": {
"plugins": [
["react-transform", {
"transforms": [{
"transform": "react-transform-hmr",
"imports": ["react"],
"locals": ["module"]
}, {
"transform": "react-transform-catch-errors",
"imports": ["react", "redbox-react"]
}, {
"transform": "./src/my-custom-transform"
}]
}]
]
}
}
}
As you can see, each transform, apart from the transform
field where you write it name, also has imports
and locals
fields. You should consult the docs of each individual transform to learn which imports
and locals
it might need, and how it uses them. You probably already guessed that this is just a way to inject local variables (like module
) or dependencies (like react
) into the transforms that need them.
Note that when using React.createClass()
and allowing babel
to extract the displayName
property you must ensure that babel-plugin-react-display-name is included before react-transform
. See this github issue for more details.
You may optionally specify an array of strings called factoryMethods
if you want the plugin to look for components created with a factory method other than React.createClass
. Note that you don’t have to do anything special to look for ES6 components—factoryMethods
is only relevant if you use factory methods akin to React.createClass
.
Writing Transforms
It’s not hard to write a custom transform! First, make sure you call your NPM package react-transform-*
so we have uniform naming across the transforms. The only thing you should export from your transform module is a function.
export default function myTransform() {
}
This function should return another function:
export default function myTransform() {
return function wrap(ReactClass) {
return ReactClass;
}
}
As you can see, you’ll receive ReactClass
as a parameter. It’s up to you to do something with it: monkeypatch its methods, create another component with the same prototype and a few different methods, wrap it into a higher-order component, etc. Be creative!
export default function logAllUpdates() {
return function wrap(ReactClass) {
const displayName =
const originalComponentDidUpdate = ReactClass.prototype.componentDidUpdate;
ReactClass.prototype.componentDidUpdate = function componentDidUpdate() {
console.info(`${displayName} updated:`, this.props, this.state);
if (originalComponentDidUpdate) {
originalComponentDidUpdate.apply(this, arguments);
}
}
return ReactClass;
}
}
Oh, how do I get displayName
?
Actually, we give your transformation function a single argument called options
. Yes, options
:
export default function logAllUpdates(options) {
It contains some useful data. For example, your options
could look like this:
{
filename: '/Users/dan/p/my-projects/src/App.js',
imports: [React],
locals: [module],
components: {
$_MyComponent: {
displayName: 'MyComponent'
},
$_SomeOtherComponent: {
displayName: 'SomeOtherComponent',
isInFunction: true
}
}
}
Of course, you might not want to use all options, but isn’t it nice to know that you have access to them in the top scope—which means before the component definitions actually run? (Hint: a hot reloading plugin might use this to decide whether a module is worthy of reloading, even if it contains an error and no React components have yet been wrapped because of it.)
So, to retrieve the displayName
(or isInFunction
, when available), use the options
parameter and the second uniqueId
parameter given to the inner function after ReactClass
:
export default function logAllUpdates(options) {
return function wrap(ReactClass, uniqueId) {
const displayName = options.components[uniqueId].displayName || '<Unknown>';
This is it!
Sure, it’s a slightly contrived example, as you can grab ReactClass.displayName
just fine, but it illustrates a point: you have information about all of the components inside a file before that file executes, which is very handy for some transformations.
Here is the complete code for this example transformation function:
export default function logAllUpdates(options) {
return function wrap(ReactClass, uniqueId) {
const displayName = options.components[uniqueId].displayName || '<Unknown>';
const originalComponentDidUpdate = ReactClass.prototype.componentDidUpdate;
ReactClass.prototype.componentDidUpdate = function componentDidUpdate() {
console.info(`${displayName} updated:`, this.props, this.state);
if (originalComponentDidUpdate) {
originalComponentDidUpdate.apply(this, arguments);
}
}
return ReactClass;
}
}
Now go ahead and write your own! Don’t forget to tag it with react-transform
keyword on npm.
Patrons
The work on React Transform, React Hot Loader, Redux, and related projects was funded by the community. Meet some of the outstanding companies that made it possible:
See the full list of React Transform patrons.
License
MIT