fix: reference possibly missing event typings

package.json

@@ -19,7 +19,7 @@
     "./package.json": "./package.json"
   },
   "scripts": {
-    "build": "pkg-utils build && pkg-utils --strict",
+    "build": "pkg-utils build && pkg-utils --strict && tsx scripts/referenceEventTypings.ts",
     "build:watch": "pkg-utils watch",
     "clean": "rimraf dist coverage",
     "lint": "eslint . && tsc --noEmit",

scripts/referenceEventTypings.ts

@@ -0,0 +1,43 @@
+import {copyFile, readdir, readFile, writeFile} from 'node:fs/promises'
+import {join as joinPath} from 'node:path'
+
+const referenceDirective = `/// <reference path="events.d.ts" />`
+
+/**
+ * Add a reference directive to the `events.d.ts` file at the top of every "type entry"
+ * file in the `dist` (output) directory. These files are eg `index.d.ts` and `index.d.cts`.
+ *
+ * This is necessary because the `events.d.ts` file contains some "shims" for APIs such as
+ * `Event`, `EventTarget` and `MessageEvent` that are technically part of the supported
+ * environments, but not always present in their typings - eg `@types/node` does not declare
+ * a global `MessageEvent` even though it is present in Node.js.
+ *
+ * Current build tooling (`@sanity/pkg-utils`) does not support adding reference directives
+ * directly, so we have to do this as a post-build step.
+ */
+async function referenceEventTypings() {
+  const distDir = joinPath(import.meta.dirname, '..', 'dist')
+  const srcDir = joinPath(import.meta.dirname, '..', 'src')
+
+  const entries = await readdir(distDir)
+
+  const typeEntries = entries.filter(
+    (entry) => entry.startsWith('index.') && (entry.endsWith('.d.ts') || entry.endsWith('.d.cts')),
+  )
+
+  for (const entry of typeEntries) {
+    const typeFile = joinPath(distDir, entry)
+    const typeFileContent = await readFile(typeFile, 'utf-8')
+
+    if (!typeFileContent.includes(referenceDirective)) {
+      await writeFile(typeFile, `${referenceDirective}\n\n${typeFileContent}`)
+    }
+  }
+
+  await copyFile(joinPath(srcDir, 'events.d.ts'), joinPath(distDir, 'events.d.ts'))
+}
+
+referenceEventTypings().catch((error) => {
+  console.error(error)
+  process.exit(1)
+})