overleaf/services/web/frontend/js/main/importing.js

import App from '../base'
App.controller(
  'ImportingController',
  function ($interval, $scope, $timeout, $window) {
    $interval(function () {
      $scope.state.load_progress += 5
      if ($scope.state.load_progress > 100) {
        $scope.state.load_progress = 20
      }
    }, 500)
    $timeout(function () {
      $window.location.reload()
    }, 5000)
    $scope.state = {
      load_progress: 20
    }
  }
)