返回 null 的 GraphQL 查询

GraphQL query returning null

我 运行 这个成功的突变被保存到我的 MongoDB 数据库中:

mutation {
  addRecipe(name: "Chole Dhania Masala", category: "Indian", description: "A tasty dish", instructions: "Cook it") {
    name
    category
    description
    instructions
  }
}

然而,当我运行查询它时:

query {
  getAllRecipes {
    _id
    name
    category
    likes
    createdDate
  }
}

我不清楚我为什么得到:

{
  "data": {
    "getAllRecipes": null
  }
}

这是我的 resolvers.js 文件:

exports.resolvers = {
    Query: {
        getAllRecipes: async (root, args, { Recipe }) => {
            const allRecipes = await Recipe.find();
            return allRecipes;
        }
    },
    Mutation: {
        addRecipe: async (root, { name, description, category, instructions, username }, { Recipe }) => {
            const newRecipe = await new Recipe({
                name,
                description,
                category,
                instructions,
                username
            }).save();
            return newRecipe;
        }
    }
};

你有recipes吗?

Query: {
    getAllRecipes: async (root, args, { Recipe }) => {
        const allRecipes = await Recipe.find();
        if (allRecipes) {
          return allRecipes;
        }

        return null;
    }
}