chore: add reflected type information to the .js files in ./build

tools/reflectTypes.mjs

@@ -0,0 +1,58 @@
+import { readFileSync, writeFileSync, readdirSync } from 'node:fs'
+import { fileURLToPath } from 'node:url'
+import { dirname, join, relative } from 'node:path'
+
+const __filename = fileURLToPath(import.meta.url)
+const __dirname = dirname(__filename)
+
+const buildDir = join(__dirname, '..', 'build')
+const files = (await readdirSync(buildDir, { recursive: true }))
+  .filter(file => file.endsWith('.js'))
+  .map(file => join(buildDir, file))
+
+for (const file of files) {
+  reflectType(file, { debug: true })
+}
+
+function reflectType(srcFile, options = { debug: false }) {
+  log(`Reflecting file "${relative(__dirname, srcFile)}"`)
+
+  const defFile = srcFile.replace(/.js$/, '.d.ts')
+  const src = String(readFileSync(srcFile))
+  const defs = String(readFileSync(defFile))
+
+  if (src.includes('.reflectedType5')) {
+    log('  Source file already contains reflected types and will be ignored')
+    return
+  }
+
+  const matches = Array.from(src.matchAll(/[^\n](export +)?const +([\w$]+) += +implementations\b/g))
+
+  if (matches.length === 0) {
+    log(`  No implementations found`)
+    return
+  }
+
+  for (const match of matches) {
+    const name = match[2]
+    log(`  Found an implementations definition: "${name}"`)
+
+    const def = new RegExp(`export declare const ${name}: {(?:(?!\n}).)+\n}`, 's').exec(defs)
+
+    if (def) {
+      log(`  Injected type definitions for "${name}"`)
+
+      const srcReflected = `${src}\n${name}.reflectedType5 = \`${def}\`\n`
+
+      writeFileSync(srcFile, srcReflected)
+    } else {
+      log(`  No type definitions found for "${name}"`)
+    }
+  }
+
+  function log(...args) {
+    if (options.debug) {
+      console.log(...args)
+    }
+  }
+}