you can now unlike

backend/routes/users.js

@@ -56,11 +56,17 @@ router.put("/unlike", async function (req, res) {
     const movieId = await req.body.movieId;
     const movieOid = await MovieModel.findOne({ id: movieId });
     const user = await UserModel.findById(userId);
-    const likedMovies = user.liked_movies.concat([movieOid._id]);
+    const likedMovies = user.liked_movies;
+    const myIndex = likedMovies.indexOf(movieOid._id);
+    if (myIndex !== -1) {
+      likedMovies.splice(myIndex, 1);
       await UserModel.findByIdAndUpdate(userId, {
         liked_movies: likedMovies,
       });
       res.send("Done");
+    } else {
+      res.send("This movie wasn't liked");
+    }
   } catch (error) {
     console.log(error);
     res.send("Internal problem");