如何在 axios 的默认配置里，处理 progress？

import axios from 'axios'

let config =  axios.create({
    withCredentials: true,
    headers:{
        'X-Requested-With': 'XMLHttpRequest'
    },
    onUploadProgress: p => { return 100 * ( p.loaded / p.total ) },
    onDownloadProgress: p => { return 100 * ( p.loaded / p.total ) }
})

export default config

import axios from 'config'
axios.post('/api', {
    onUploadProgress (a){
        console.log(a)
    },
    onDownloadProgress (a){
        console.log(a)
    }
})