Switch back to CommonJS modules

A primary goal of Miniflare is to provide a *fun* developer
experience. Currently, this is not the case when using Miniflare with
a certain popular testing framework (**cough**, ~~Jest~~, **cough**),
because it and its ecosystem's support for ESM isn't great yet.

This also makes it easier to upgrade from Miniflare 1. Node lets
you import CommonJS modules in ES modules so this won't break those.
We'll look at switching to ES modules again later...

- Switch esbuild format to `cjs` and set platform to `node`
- Replace `"type": "module"` and `"exports"` with `"main"` in
  `package.json`s
- Replace all dynamic `import()`s with `require()`s
- Remove all uses of `import.meta.url`
- Use `@ava/typescript` for tests instead of custom TypeScript loader

Closes #119
Co-authored-by: Kikobeats <[email protected]>

Author: mrbbot

.eslintrc.js

@@ -1,7 +1,7 @@
 module.exports = {
   parser: "@typescript-eslint/parser",
   extends: ["plugin:prettier/recommended"],
-  plugins: ["import"],
+  plugins: ["import", "es"],
   rules: {
     "import/order": ["warn", { alphabetize: { order: "asc" } }],
     "no-undef-init": "off",
@@ -17,10 +17,12 @@ module.exports = {
         "@typescript-eslint/no-empty-function": "off",
         "@typescript-eslint/no-explicit-any": "off",
         "@typescript-eslint/no-non-null-assertion": "off",
+        "@typescript-eslint/no-var-requires": "off",
         "@typescript-eslint/no-unused-vars": [
           "warn",
           { argsIgnorePattern: "^_" },
         ],
+        "es/no-dynamic-import": "error",
       },
     },
   ],

ava.config.js

@@ -0,0 +1,21 @@
+import { pkgsList } from "./scripts/common.mjs";
+
+const rewritePaths = Object.fromEntries(
+  pkgsList.map((pkgName) => [
+    `packages/${pkgName}/test/`,
+    `packages/${pkgName}/dist/test/`,
+  ])
+);
+
+export default {
+  nonSemVerExperiments: {
+    nextGenConfig: true,
+  },
+  files: ["packages/*/test/**/*.spec.ts"],
+  timeout: "5m",
+  nodeArguments: ["--no-warnings", "--experimental-vm-modules"],
+  typescript: {
+    compile: false,
+    rewritePaths,
+  },
+};

ava.config.mjs

@@ -44,6 +44,7 @@
     "esbuild": "^0.12.20",
     "eslint": "^7.32.0",
     "eslint-config-prettier": "^8.3.0",
+    "eslint-plugin-es": "^4.1.0",
     "eslint-plugin-import": "^2.24.2",
     "eslint-plugin-prettier": "^3.4.1",
     "esm": "^3.2.25",

package-lock.json

@@ -11,8 +11,7 @@
   ],
   "author": "MrBBot <[email protected]>",
   "license": "MIT",
-  "type": "module",
-  "exports": "./dist/src/index.js",
+  "main": "./dist/src/index.js",
   "types": "./dist/src/index.d.ts",
   "files": [
     "dist/src"

package.json

@@ -11,8 +11,7 @@
   ],
   "author": "MrBBot <[email protected]>",
   "license": "MIT",
-  "type": "module",
-  "exports": "./dist/src/index.js",
+  "main": "./dist/src/index.js",
   "types": "./dist/src/index.d.ts",
   "files": [
     "dist/src"

packages/cache/package.json

@@ -1,6 +1,5 @@
 import { readFileSync } from "fs";
 import path from "path";
-import { fileURLToPath } from "url";
 import {
   MiniflareError,
   OptionMetadata,
@@ -92,8 +91,6 @@ export function parseArgv<Plugins extends PluginSignatures>(
   // If help or version requested, ignore other options
   if (parsed.help) throw new ParseError("ERR_HELP");
   if (parsed.version) {
-    const __filename = fileURLToPath(import.meta.url);
-    const __dirname = path.dirname(__filename);
     const pkgPath = path.join(__dirname, "..", "..", "package.json");
     const pkg = JSON.parse(readFileSync(pkgPath, "utf8"));
     throw new ParseError("ERR_VERSION", pkg.version);

packages/cli-parser/package.json

@@ -11,8 +11,7 @@
   ],
   "author": "MrBBot <[email protected]>",
   "license": "MIT",
-  "type": "module",
-  "exports": "./dist/src/index.js",
+  "main": "./dist/src/index.js",
   "types": "./dist/src/index.d.ts",
   "files": [
     "dist/src"

packages/cli-parser/src/parse.ts

@@ -326,7 +326,7 @@ export class MiniflareCore<
       this.#wranglerConfigPath = configPath;
       try {
         const configData = await fs.readFile(configPath, "utf8");
-        const toml = await import("@iarna/toml");
+        const toml: typeof import("@iarna/toml") = require("@iarna/toml");
         const config: WranglerConfig = toml.parse(configData);
         if (configEnv && config.env && configEnv in config.env) {
           // TODO: take into account option inheritance properly
@@ -730,9 +730,11 @@ export class MiniflareCore<
       let watcher = this.#watcher;
       // Make sure we've created the watcher
       if (!watcher) {
-        const { Watcher } = await import("@miniflare/watcher");
+        const {
+          Watcher,
+        }: typeof import("@miniflare/watcher") = require("@miniflare/watcher");
         this.#watcherCallbackMutex = new Mutex();
-        watcher = new Watcher(this.#watcherCallback.bind(this)); // , this.log
+        watcher = new Watcher(this.#watcherCallback.bind(this));
         this.#watcher = watcher;
       }