add a simple script to validate the package.json exports with the build output

src/Umbraco.Web.UI.Client/devops/package/validate-exports.js

@@ -0,0 +1,18 @@
+import { readFileSync } from 'fs';
+import { globSync } from 'glob';
+
+const packageJsonPath = 'package.json';
+const packageJsonData = JSON.parse(readFileSync(packageJsonPath).toString());
+const packageJsonExports = packageJsonData.exports;
+
+// Iterate over the exports in package.json
+for (const [key, value] of Object.entries(packageJsonExports || {})) {
+	if (value) {
+		const jsFiles = await globSync(value);
+
+		// Log an error if the export from the package.json does not exist in the build output
+		if (jsFiles.length === 0) {
+			console.error(`Could not find export: ${key} -> ${value} in the build output.`);
+		}
+	}
+}