How do I define a file name key in a for loop?

Probably a basic question, I need the formData.delete(key) function to delete the value of the "file[]" filename key. It's my understanding the the "file" value in formData.append is the uploaded file, and by deleting the value, I remove the file. I'm not sure what to subsitute for "key" in formData.delete(key) to reference the specific "file[]" key name.

As of now, I get 'Uncaught ReferenceError: key is not defined', expectedly, when I click the deleteButton element.

const formData = new FormData();

  dropZone.addEventListener("drop", (event) => {
    for (const file of event.dataTransfer.files) {
      formData.append("file[]", file);
      const listItem = document.createElement("li");
      listItem.textContent = file.name + "  ";
      console.log(file.name);
      const deleteButton = document.createElement("button");
      deleteButton.classList.add("button", "button-small");
      deleteButton.textContent = " Remove";
      deleteButton.addEventListener("click", () => {
        formData.delete(key);
        listItem.remove();
      });
      listItem.appendChild(deleteButton);
      filesList.appendChild(listItem);
    }
  });

I tried defining a local variable fileName = "file[]" and passing that in as the appended key, and passing that as the key name in formData.delete. This stopped any files from being appended in the ultimate post request, seemingly. This was kind of shooting in the dark, as my Javascript isn't very good.

const formData = new FormData();

  dropZone.addEventListener("drop", (event) => {
    for (const file of event.dataTransfer.files) {
      var fileName = "file[]";
      formData.append(fileName, file);
      const listItem = document.createElement("li");
      listItem.textContent = file.name + "  ";
      console.log(file.name);
      const deleteButton = document.createElement("button");
      deleteButton.classList.add("button", "button-small");
      deleteButton.textContent = " Remove";
      deleteButton.addEventListener("click", () => {
        formData.delete(fileName);
        listItem.remove();
      });
      listItem.appendChild(deleteButton);
      filesList.appendChild(listItem);
    }
  });

I have tried formData.delete(file), but that is not removing the file from the ultimate post request.