Frontend Vite File Upload

Admin File Upload

Different from backend — frontend builds FormData, backend handles two-phase save.

API Layer

export const createCategory = async (data: CreateCategoryPayload) => {
  const formData = new FormData();
  Object.entries(data).forEach(([key, value]) => {
    if (value != null && !['imageUrl', 'coverUrl'].includes(key)) {
      formData.append(key, value.toString());
    }
  });
  if (data.imageUrl) formData.append('imageUrl', data.imageUrl);
  if (data.coverUrl) formData.append('coverUrl', data.coverUrl);

  return (await api.post('/category/create-category', formData, {
    headers: { 'Content-Type': 'multipart/form-data' },
  })).data;
};

Exclude file keys from Object.entries loop — append File objects separately.

Form UI

<input type="file" accept="image/*" hidden ref={fileRef} />
<Button type="button" => fileRef.current?.click()}>Upload</Button>
{preview && <img src={preview} alt="Preview" />}

const handleFileChange = (e: ChangeEvent<HTMLInputElement>) => {
  const file = e.target.files?.[0];
  if (!file?.type.startsWith('image/')) { toast.error('Image only'); return; }
  if (file.size > 5 * 1024 * 1024) { toast.error('Max 5MB'); return; }
  setImageFile(file);
  setPreview(URL.createObjectURL(file));
};

Submit

await createMutation.mutateAsync({ ...formData, imageUrl: imageFile ?? undefined });

Edit Form — Current vs New

Show existing: `${API_URL}${entity.imageUrl}` Show new preview from FileReader/ObjectURL alongside.

JSON Fallback (products)

If no files, some endpoints accept JSON body instead of FormData.

Axios Note

No default Content-Type on axios instance — allows multipart boundary auto-set.