Experiments#

The experiments configuration is used to enable experimental capabilities in the plugin.

• Example

new ModuleFederationPlugin({
  name: '@demo/host',
  experiments: {
    federationRuntime: 'hoisted'
  },
  shared: {
    react: {
      singleton: true,
    },
    'react-dom': {
      singleton: true,
    },
  },
  //...
});

federationRuntime#

• Type: enum
• Required: No
• Default: false
• Options: false | "hoisted"

Hoisted Runtime#

When the runtime is hoisted, the following occurs:

These configurations are useful for:

• Setting or usingruntimeChunk: 'single'.
• Avoiding the import() at the top of the app or in the entry point of user code to prevent eager consumption errors. In the past, this was often mandatory and commonly seen as import('./bootstrap.js') in example apps.
• Moving the Module Federation runtime packages into runtime chunks, keeping them out of the entry point - reducing code duplication

1. Optimizations

The module-federation/runtime is patched onto entrypoints. This causes multiple copies to exist in some builds. It also causes some "eager consumption" errors when chunk splitting is configured in certain ways.

This resolves a common issue with runtimeChunk: single

2. Async startup

Entrypoint startup will switch to "active" initialization and use async dependency startup.

You will no longer need a mandatory import('./bootsrtap') dynamic import in order for consumers / hosts to function. There should be no "eager consumption" errors possible, as the initialization of the files themselves behave as async chunks.

3. Eager Runtime Access

Instead of federation runtime initilizing in the entrypoint code, it is initialized in a RuntimeModule, within the webpack runtime. This allows module federation to be avaliable ahead of time, thus enabling "Async Startup" capabilities etc.

externalRuntime#

• Type: boolean
• Required: No
• Default: false

After setting true, the external MF runtime will be used and the runtime provided by the consumer will be used. (Please make sure your consumer has provideExternalRuntime: true set, otherwise it will not run properly!)

provideExternalRuntime#

• Type: boolean
• Required: No
• Default: false

Setting true will inject the MF runtime at the consumer.