@writ/utils/request-fetch-progress-fake.js

My tool kit

import progressSpeedmeter from './progress-speedmeter';

/**
 * 上传进度 
 * @param {number} length 
 * @param {function} onProgress 
 * @param {number} delay 
 */
export default function fakeProgress(length, onProgress, delay) {
   const ret = res => res;

   if (length > 0) {
      const startTime = Date.now();
      const progress = {
         length, // 文件总长度
         transferred: 0, // 已发送
         runtime: startTime, // 已耗时
         percentage: 0, // 已上传的占比 
      };
      const speedometer = progressSpeedmeter(length);
      const getProgress = function (percent) {
         progress.percentage = percent;
         progress.runtime = Date.now() - startTime;
         progress.transferred = length * progress.percentage;
         onProgress(progress);
      };
      const timer = setInterval(function () {
         getProgress(speedometer(progress.percentage));
      }, delay > 30 ? delay : 30);

      ret.end = function () {
         getProgress(1);
         clearInterval(timer);
      };
   } else {
      ret.end = function () { };
   }

   return ret;
}