Merge pull request #67 from FirebasePrivate/rjh-onWrite

Fix a stale error message: users now use .onWrite() rather than .on()

Author: Robert-Jan Huijsman

src/builders/database-builder.ts

@@ -37,7 +37,7 @@ export default class DatabaseBuilder extends FunctionBuilder {
     handler: (event: Event<DatabaseDeltaSnapshot>) => PromiseLike<any> | any
   ): CloudFunction {
     if (!this._path) {
-      throw new Error('Must call .path(pathValue) before .on() for database function definitions.');
+      throw new Error('Must call .path(pathValue) before .onWrite() for database function definitions.');
     }
     return this._makeHandler(handler, 'data.write');
   }