Add explicit return type

Author: benjie

packages/graphql-language-service-server/src/parsers/babel.ts

@@ -1,8 +1,11 @@
-import { parse, ParserPlugin } from '@babel/parser';
+import { parse, ParseResult, ParserPlugin } from '@babel/parser';
 import { BABEL_PLUGINS, PARSER_OPTIONS } from '../constants';
 import { SourceParser } from './types';
 
-export const babelParser = (text: string, plugins?: ParserPlugin[]) => {
+export const babelParser = (
+  text: string,
+  plugins?: ParserPlugin[],
+): ParseResult => {
   const babelPlugins = [...BABEL_PLUGINS];
   if (plugins) {
     babelPlugins.push(...plugins);