TS: Allow to pass object as graphiql option

types/index.d.ts

@@ -39,6 +39,15 @@ declare namespace graphqlHTTP {
  | OptionsResult;
  type OptionsResult = OptionsData | Promise<OptionsData>;
 
+ interface GraphiQLOptions {
+ /**
+ * An optional GraphQL string to use when no query is provided and no stored
+ * query exists from a previous session. If undefined is provided, GraphiQL
+ * will use its own default query.
+ */
+ defaultQuery: string;
+ }
+
  interface OptionsData {
  /**
  * A GraphQL schema from graphql-js.
@@ -121,8 +130,9 @@ declare namespace graphqlHTTP {
 
  /**
  * A boolean to optionally enable GraphiQL mode.
+ * Alternatively, instead of `true` you can pass in an options object.
  */
- graphiql?: boolean | null;
+ graphiql?: boolean | GraphiQLOptions;
 
  /**
  * A resolver function to use when one is not provided by the schema.