问res.json不能正确地使用axios / React

EN

//frontend 
    const fetchRewards = async()=>{
                    let link ="/api/reward";
                    const {data} = await axios.get(link);
                    console.log(data); **// this one logging undefined**
                }

// on controller
     async getRewardsById(req,res,next) {
                try {
                    const result = await rewardService.getReward();
                    res.json(result);
                } catch (error) {
                    next(error);
                }
            },

const getReward = async () => {
 
  fs.readFile("test.json", (err, inputData) => {
    return {"name":"John", "age":30, "car":null};
 }

  console.log("done");
}