📚 Modules

• Modules ReferenceOpen external link

​Enabling Modules

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

Using the CLICLI
Using wrangler.tomlwrangler.toml
Using the APIJavaScript API
$ miniflare --modules # or -m
wrangler.toml
[build.upload]
format = "modules"
const mf = new Miniflare({
  modules: true,
});

When using the API you must also pass the --experimental-vm-modules flag to Node.js. This is added automatically when using the CLI.

You can now 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...");
  },
};

​Module Rules

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

Using the CLICLI
Using wrangler.tomlwrangler.toml
Using the APIJavaScript API
# Note all rules implicitly have the `fallthrough` option set to true
$ miniflare --modules-rule "ESModule=**/*.js" --modules-rule "Text=**/*.txt"
wrangler.toml
[[build.upload.rules]]
type = "ESModule"
globs = ["**/*.js"]
[[build.upload.rules]]
type = "Text"
globs = ["**/*.txt"]
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:

[[build.upload.rules]]
type = "ESModule"
globs = ["**/*.mjs"]
[[build.upload.rules]]
type = "CommonJS"
globs = ["**/*.js", "**/*.cjs"]