diff --git a/docs/testing.md b/docs/testing.md
index f185d0eac486..e3504d418de3 100644
--- a/docs/testing.md
+++ b/docs/testing.md
@@ -281,6 +281,7 @@ const createJestConfig = nextJest({
 })
 
 // Add any custom config to be passed to Jest
+/** @type {import('jest').Config} */
 const customJestConfig = {
   // Add more setup options before each test is run
   // setupFilesAfterEnv: ['<rootDir>/jest.setup.js'],