@fronts/mf

@fronts/mf is the Module Federation 2 transport adapter for Fronts applications.

pnpm add @fronts/core @fronts/mf @module-federation/runtime

@module-federation/runtime is a peer dependency. Supply an explicit official runtime instance; the adapter does not create or discover a global default instance. Fronts is currently alpha, so protocol and API changes may occur before 2.0 stable.

Create the adapter

import { createInstance } from '@module-federation/runtime';
import { createFrontsHost, createStaticResolver } from '@fronts/core';
import { createModuleFederationAdapter, createModuleFederationSource } from '@fronts/mf';

const federation = createInstance({ name: 'shell', remotes: [] });
const source = createModuleFederationSource({
  name: 'checkout_2_4_1',
  entry: 'https://cdn.example.com/checkout/2.4.1/mf-manifest.json',
});

const host = createFrontsHost({
  resolver: createStaticResolver([
    { match: { name: 'checkout' }, resolve: { source, version: '2.4.1' } },
  ]),
  loader: createModuleFederationAdapter({ instance: federation }),
});

For each resolved application, the adapter uses only public instance methods: registerRemotes(), preloadRemote(), and loadRemote(). It does not parse manifests, select shared dependencies, modify snapshots, or import @module-federation/runtime-core; those remain official Module Federation responsibilities.

Remote binding rules

The official runtime keeps the first registration when a remote name is registered again without force. The adapter therefore rejects a different source or known resolved version previously registered through Fronts on the same runtime instance. Prefer an immutable, deployment-specific remote name. Use force only when intentionally replacing runtime cache; normal rollout should use registry promotion and a Fronts replacement transaction.

The remote module must default-export a valid FrontsApp, normally from an expose named ./application. A component or Bridge application alone does not automatically satisfy the Fronts ABI. See the Module Federation integration matrix for the verified producer boundary.

Lifecycle ownership

The resolver chooses a concrete source, this adapter performs transport loading, and the Host owns validation, service scope, container preparation, readiness, and cleanup. An explicit runtime instance lets the composition root control plugins, share scopes, and transport lifetime without accidentally sharing hidden process-wide state. After disposing the Fronts Host, dispose any runtime plugin or external-client resources separately owned by that composition root.