Axios with QueryString form data.

axios-demo.js

import axios from 'axios'
import qs from 'qs'

const axiosInstance = axios.create({
  transformRequest: [function(data) {
    return qs.stringify(data);
  }],
  headers:{
    'Content-Type': 'application/x-www-form-urlencoded'
  }
})

// Send a POST request
axiosInstance({
  method: 'post',
  url: '/demo/12345',
  data: {
    key1: 'value1',
    key2: 'value2'
  }
}).then(function(response) {
    console.log(response)
  })
  .catch(function(error) {
    console.log(error)
  })