chore(NODE-5277): add definition clean up script (#576)

Author: nbbeeken

etc/clean_definition_files.cjs

@@ -0,0 +1,35 @@
+#! /usr/bin/env node
+/* eslint-disable @typescript-eslint/no-var-requires */
+const fs = require('fs');
+const path = require('path');
+
+function* walk(root) {
+  const directoryContents = fs.readdirSync(root);
+  for (const filepath of directoryContents) {
+    const fullPath = path.join(root, filepath);
+    const stat = fs.statSync(fullPath);
+    if (stat.isDirectory()) {
+      yield fullPath;
+      yield* walk(fullPath);
+    } else if (stat.isFile()) {
+      yield fullPath;
+    }
+  }
+}
+
+const libPath = path.resolve(__dirname, '..', 'lib');
+if (fs.existsSync(libPath)) {
+  const definitionFiles = Array.from(walk(libPath))
+    .filter(filePath => filePath.endsWith('.d.ts') || filePath.endsWith('.d.ts.map'));
+
+  for (const definitionFile of definitionFiles) {
+    fs.unlinkSync(definitionFile);
+  }
+
+  const emptyDirectories = Array.from(walk(libPath))
+    .filter(filePath => fs.statSync(filePath).isDirectory() && fs.readdirSync(filePath).length === 0);
+
+  for (const emptyDirectory of emptyDirectories) {
+    fs.rmdirSync(emptyDirectory);
+  }
+}