This in Axios configuration file is undefined?

problem description

found that this attribute is not found in this.$router, then check that this is undefined

related codes

/ / Please paste the code text below (do not replace the code with pictures)
import axios from "axios"
import {Loading, Message} from" element-ui"
import Debounce from "lodash/debounce"

const Axios = axios.create ({

)

baseURL:"/",
timeout:"10000",
responseType:"json",
withCredentials:true,
headers:{
    "Content-Type":"application/json; charset=UTF-8"
}

});
let needLoadingRequestCount = 0;
let loadingObj;

Axios.interceptors.request.use (

)

config=>{
    console.log(this);
    if(config.showLoading){
        showFullScreenLoading();
    }
    return config;
},
error=>{
    if(needLoadingRequestCount !== 0){
        loadingObj.close();
    }
    Message({
        showClose:true,
        message:"",
        type:"error"
    });
    return Promise.reject(error);
}

);

Axios.interceptors.response.use (

)

res =>{
    // console.log(this);
    if(res.config.showLoading){
        tryHideFullScreenLoading();
    }
    if(res.data.code !== 200 && res.data.message){
        Message({
            showClose:false,
            type:"error",
            center:true,
            message:res.data.message ? res.data.message : "! "
        });
        if(res.data.code === 9999100){
            this.$router.push("/login");
        }
        return Promise.reject(res.data.message);
    }
    return res;
},
error =>{
    if(needLoadingRequestCount !== 0){
        loadingObj.close();
    }
    Message({
        showClose:true,
        message:"",
        type:"error"
    });
    return Promise.reject(error);
}

);

function showFullScreenLoading () {

if(needLoadingRequestCount === 0){
    loadingObj = Loading.service({
                    lock:true,
                    text:"Loading",
                    spinner: "el-icon-loading",
                    background: "rgba(0, 0, 0, 0.7)"
                });
}
needLoadingRequestCount PP

}
function tryHideFullScreenLoading () {

if(needLoadingRequestCount <= 0) return
    needLoadingRequestCount --
if(needLoadingRequestCount === 0){
    Debounce(tryCloseLoading,300)();
}

}
function tryCloseLoading () {

if(needLoadingRequestCount === 0){
    loadingObj.close();
}

}
export default {

header(token){
    Axios.defaults.headers.common["Authorization"] = `ticket ${token}`;
},
post:(url,data,config = {showLoading : true}) => Axios.post(url,data,config),
get:(url,config = {showLoading : true}) => Axios.get(url,config),
delete:(url,config = {showLoading : true}) => Axios.delete(url,config)

}

what result do you expect? What is the error message actually seen?

they are all arrow functions. How could this be lost