在開(kāi)發(fā)微信小程序的時(shí)候，出現(xiàn)了詭異的現(xiàn)象參考代碼如下：//在函數(shù)外部聲明兩個(gè)變量var userName,portrait; wx.getUserInfo({     success: function (res) {        var userInfo=res.userInfo;        //變量可以正常傳遞到wx.getUserInfo函數(shù)中被賦值         userName=userInfo.nickName;         portrait=userInfo.avatarUrl;     } });this.database.collection("Comment").add({     data: {        //問(wèn)題點(diǎn)：編輯器提示變量尚未初始化         userName: userName,         portrait: portrait     } });已經(jīng)將問(wèn)題點(diǎn)在代碼中用注釋標(biāo)識(shí)出來(lái)，編輯器提示Variable might not have been initialized，為什么在回調(diào)函數(shù)中對(duì)變量賦值無(wú)效？如何解決？