解决：TypeError: Cannot read properties of undefined (reading 'service')

vue 3.x 版本加载转圈圈实例有变更，按下面导入

import { ElLoading} from 'element-plus'

this.loadingInstance = ElLoading.service({
                target: '.main',
                text: '玩命加载中',
                background: 'rgba(0,0,0,0.5)'
            }