show percent upload

    gcode_changed () {

      this.is_uploading_gcode = true

      this.gcode_upload_progress = 0

      let req_id = parseInt(this.id)

      var formData = new FormData();

      var progressHandler = function(progressEvent) {

        console.log(progressEvent)

        var percentCompleted = Math.round((progressEvent.loaded * 100) / progressEvent.total)

        console.log(percentCompleted)

        this.gcode_upload_progress = percentCompleted

      }

<template>

  <div v-if="is_connected">

    <v-overlay :value="show_error_overlay" fullscreen>

      <v-alert type="error">MyFab Client had a problem. Please reload the page.<br/>

        If the problem continues, inform the DVIC or Fablab team by describing what you were doing and with the following message: <br/>

        <code>{{ error_message }}</code></v-alert>

    </v-overlay>

    <v-navigation-drawer v-model="nav" absolute>

      <v-list-item class="px-2">

        <v-list-item-avatar>

      <v-app-bar-nav-icon @click="nav=true"></v-app-bar-nav-icon>&nbsp;

      <v-icon>mdi-printer-3d</v-icon>&nbsp;&nbsp;MyFab2 Pre-α

      <v-spacer></v-spacer>

      <v-alert v-if="show_error_overlay" type="error">

        Problem Detected, attempting reconnection... <code>{{ error_message }}</code>

      </v-alert>

      <v-spacer></v-spacer>

      <v-img max-height="50px" max-width="60px" src="static/DVIC.png" />&nbsp;&nbsp;&nbsp;&nbsp;

      <v-img max-height="50px" max-width="45px" src="static/dvfl.png" />

    </v-toolbar>

      show: true,

      msg: msg

    };

    setTimeout(() => {

      state.global_error.show = false

    }, 2000)

  },

  not_connected(state) {

    state.not_connected = true;