HMR_API.md

id	title
hmr_api	Haul HMR API

Module haul/hot/patch.js

Usage:

import 'haul/hot/patch';
// or
require('haul/hot/patch');

Description:

• In production (NODE_ENV === 'production'): does nothing.

• In development with HMR enabled (NODE_ENV !== 'production' && module.hot):

  Patches React's createElement and createFactory, so that they use react-proxy and return a proxied component. Those components behave like the normal ones, but have their state persisted between updates.

  This file is automatically imported before all configured entry points, since the code must be executed at the very beginning.

Module haul/hot/index.js

import {
  makeHot,
  redraw,
  tryUpdateSelf,
  callOnce,
  clearCacheFor
} from 'haul/hot';

makeHot

Wrap the initial root component factory with HotWrapper, which allows for force deep update of the components tree and servers as an error boundary. This function should be called only once, upon app's initial render.

In case of multi root component app, the second argument is used for differentiating the factories. When calling redraw, the same id must be passed as a 2nd argument.

Syntax:

makeHot(
  rootFactory: () => ReactComponent,
  id?: string = 'default'
): () => ReactComponent

• rootFactory: () => ReactComponent - Initial root component factory, used to render the app's tree for the first time.

• id?: string = 'default' - Identifier of the root component factory in case of multi root component project.

Usage:

AppRegistry.registerComponent('MyApp', makeHot(() => MyApp));
// named factory
AppRegistry.registerComponent('MyApp', makeHot(() => MyApp, 'MyApp'));

---

redraw

Redraw the wrapped root component with a new (updated) tree from given factory function. The function accepts another function, which must return a React component with a new tree. Should be used only for component wrapped with makeHot.

In case of multi root component project, you must specify the id of the root component, which should be updated and re-rendered.

Syntax:

redraw(newRootFactory: () => ReactComponent, id?: string = 'default'): void

• newRootFactory: () => ReactComponent - Root component factory with new updates.

• id?: string = 'default' - Identifier of the root component factory in case of multi root component project.

Usage:

redraw(() => require('./file').default);
// or
redraw(() => require('./file').default, 'MyApp');

---

tryUpdateSelf

Tries to re-render the root component. Only useful if your root component and call to registerComponent (or similar) resides in the same file. Then, upon update the module is reevaluated, but the app's component tree, remains the same unless this function is called.

Syntax:

tryUpdateSelf(): void

Usage:

tryUpdateSelf();

---

callOnce

Ensures the given function will be called only once. Useful for calling function with side effects only once.

Syntax:

callOnce(callback: () => void): void

• callback: () => void - Function which should be called only once.

Usage:

callOnce(() => {
  AppRegistry.registerComponent('MyApp', () => MyApp);
});

---

clearCacheFor

Clears cache for gived module.

Syntax:

clearCacheFor(resolvedModuleId: string): void

• resolvedModuleId: string - fully resolved (with require.resolve) module ID.

Usage:

clearCacheFor(require.resolve('./file.js'));