diff --git a/src/transpile.ts b/src/transpile.ts
index fe42a55..dd8c1b5 100644
--- a/src/transpile.ts
+++ b/src/transpile.ts
@@ -19,7 +19,7 @@ export function getTsProgram(opts: DocsParseOptions) {
       );
     }
     const tsconfigDir = path.dirname(opts.tsconfigPath);
-    rootNames = configResult.config.files.map((f: string) => {
+    rootNames = (configResult.config.files ?? []).map((f: string) => {
       return path.join(tsconfigDir, f);
     });
     options = configResult.config.compilerOptions;