📚 Modules

• Modules Reference

Enabling Modules

Miniflare supports both the traditional service-worker and the newer modules formats for writing workers. To use the modules format, enable it with:

const mf = new Miniflare({
  modules: true,
});

You can then use modules worker scripts like the following:

export default {
  async fetch(request, env, ctx) {
    // - `request` is the incoming `Request` instance
    // - `env` contains bindings, KV namespaces, Durable Objects, etc
    // - `ctx` contains `waitUntil` and `passThroughOnException` methods
    return new Response("Hello Miniflare!");
  },
  async scheduled(controller, env, ctx) {
    // - `controller` contains `scheduledTime` and `cron` properties
    // - `env` contains bindings, KV namespaces, Durable Objects, etc
    // - `ctx` contains the `waitUntil` method
    console.log("Doing something scheduled...");
  },
};

String scripts via the script option are supported using the modules format, but you cannot import other modules using them. You must use a script file via the scriptPath option for this.

Module Rules

Miniflare supports all module types: ESModule, CommonJS, Text, Data and CompiledWasm. You can specify additional module resolution rules as follows:

const mf = new Miniflare({
  modulesRules: [
    { type: "ESModule", include: ["**/*.js"], fallthrough: true },
    { type: "Text", include: ["**/*.txt"] },
  ],
});

Default Rules

The following rules are automatically added to the end of your modules rules list. You can override them by specifying rules matching the same globs:

[
  { type: "ESModule", include: ["**/*.mjs"] },
  { type: "CommonJS", include: ["**/*.js", "**/*.cjs"] },
];