i wanna save my uploaded images in a folder firebase storage

i wanna save my uploaded images in a folder called “course-cover” in firebase storage this is my code that saves uploaded images in the route of storage directly but instead of thet i wanna save them in the “course-cover” folder

 async function storeCoverCourse(coverCourse) {
  return new Promise((resolve, reject) => {
    const storage = getStorage();
    const filename = `${coverCourse.name}-${uuidv4()}`;
    const storageRef = ref(storage, filename);
    const uploadTask = uploadBytesResumable(storageRef, coverCourse);
    uploadTask.on(
      "state_changed",
      (snapshot) => {
        // Observe state change events such as progress, pause, and resume
        // Get task progress, including the number of bytes uploaded and the total number of bytes to be uploaded
        const progress =
          (snapshot.bytesTransferred / snapshot.totalBytes) * 100;
        console.log("Upload is " + progress + "% done");
        switch (snapshot.state) {
          case "paused":
            console.log("Upload is paused");
            break;
          case "running":
            console.log("Upload is running");
            break;
        }
      },
      (error) => {
        // Handle unsuccessful uploads
        reject(error);
      },
      () => {
        // Handle successful uploads on complete
        // For instance, get the download URL: https://firebasestorage.googleapis.com/...
        getDownloadURL(uploadTask.snapshot.ref).then((downloadURL) => {
          resolve(downloadURL);
        });
      }
    );
  });
}

const imgUrls = await Promise.all(
  [...cover].map((coverCourse) => storeCoverCourse(coverCourse))
).catch((error) => {
  toast.error("image not uploaded");
  return;
});

const formDataCopy = {
  ...formData,
  imgUrls,
  timestamp: serverTimestamp(),
};
delete formDataCopy.cover;
await addDoc(collection(db, "courses"), formDataCopy);

Answer

In addition to the solution that @Dharmaraj covered in their answer, you should also get rid of the problematic use of the Promise constructor with Promise returning functions. It can be eliminated because the uploadTask object is a thenable/promise-like object.

async function storeCoverCourse(coverCourse) {
  const storage = getStorage();
  const filename = `course-cover/${coverCourse.name}-${uuidv4()}`;
  const storageRef = ref(storage, filename);
  const uploadTask = uploadBytesResumable(storageRef, coverCourse);
  
  uploadTask.on(
    "state_changed",
    (snapshot) => {
      // Observe state change events such as progress, pause, and resume
      // Get task progress, including the number of bytes uploaded and the total number of bytes to be uploaded
      const progress =
        (snapshot.bytesTransferred / snapshot.totalBytes) * 100;
      console.log("Upload is " + progress + "% done");
      switch (snapshot.state) {
        case "paused":
          console.log("Upload is paused");
          break;
        case "running":
          console.log("Upload is running");
          break;
      }
    }
  );

  return uploadTask
    .then(snapshot => snapshot.ref.getDownloadURL());
}