React Proxy

A generic React component proxy useful for hot reloading.

Requirements

React 0.14+

Usage

Intended to be used from hot reloading tools like React Hot Loader.
If you’re an application developer, it’s unlikely you’ll want to use it directly.

You will need something like react-deep-force-update to re-render the component tree after applying the update.

import React, { Component } from 'react';

class ComponentVersion1 extends Component {
  render() {
    return <div>Before hot update.</div>;
  }
}

class ComponentVersion2 extends Component {
  render() {
    return <div>After hot update.</div>;
  }
}

Without React Proxy:

const rootEl = document.getElementById('root');
React.render(<ComponentVersion1 />, rootEl);

// Will reset state and kill DOM :-(
React.render(<ComponentVersion2 />, rootEl);

With React Proxy:

import React from 'react';
import { render } from 'react-dom';
import createProxy from 'react-proxy';
import deepForceUpdate from 'react-deep-force-update';

// Create a proxy object, given the initial React component class.
const proxy = createProxy(ComponentVersion1);

// Obtain a React class that acts exactly like the initial version.
// This is what we'll use in our app instead of the real component class.
const Proxy = proxy.get();

// Render the component (proxy, really).
const rootInstance = render(<Proxy />, rootEl);

// Point the proxy to the new React component class by calling update().
// Instances will stay mounted and their state will be intact, but their methods will be updated.
proxy.update(ComponentVersion2);

// Force-update the whole React component tree.
// Until React provides an official DevTools API to do this,
// you should keep the reference to the root instance(s).
deepForceUpdate(rootInstance);

React Native

This will work with React Native when facebook/react-native#2985 lands.
For now, you can keep using 1.x.

Features

Supports both classic (React.createClass()) and modern (ES6 classes) style
Supports inherited and base classes (although you shouldn’t use inheritance with React)
Supports classic createClass() autobinding and modern autobind-decorator
Contains an extensive test suite to avoid regressions
Preserves displayName
Preserves enumerability and writability of methods
Preserves toString() of methods
Replaces instance getters and setters
Replaces instance methods preserving their identity
Replaces bound instance methods preserving their identity
Because identity is preserved, instance methods already scheduled for setInterval or setTimeout are updated
Replaces static getters and setters
Replaces unbound static methods
Replaces static properties unless they were overwritten by code

Known Limitations

Does not replace ES7 instance properties
Does not replace bound static methods
Replacing a method using autobind-decorator causes its identity to change

Contributing

Clone the repository
Run npm install
Run npm run test:watch
Take a look at the existing tests
Add tests for the failing case you aim to fix and make them pass
Submit a PR!

License

MIT

akorchev/react-proxy