怎么实现wx.request的同步

• 需求的场景描述（希望解决的问题）

let buf;               if (bluetoothType == "jeez") {    //简易蓝牙的指令                 buf = that.string2buffer("open:05s");               }               if (bluetoothType == "mac") {     //门禁机的指令                 buf = that.string2buffer("-b&-3-12069-");               }               if (bluetoothType == "jz") {      //嵌入式门禁开门指令                 //获取用户的门禁权限列表                 let powerList_url = 'CustomerAPI/Index.aspx?method=getdoorsauthpool&clientcode=559574802685&doornumber=qrs001';                 http.get(powerList_url).then(res => {                   // let hex = '0101fe 010201'                   let hex = res.data;                   //16进制字符串转为ArrayBuffer                   let typedArray = new Uint8Array(hex.match(/[\da-f]{2}/gi).map(function (h) {                     return parseInt(h, 16)                   }))                   buf = typedArray.buffer                 }).catch(res => {                   });               }               //发送开门指令               wx.writeBLECharacteristicValue({                 deviceId: deviceId,                 serviceId: serviceId,                 characteristicId: write_id,                 value: buf,                 success: function (res) {                   console.log("buf", buf);                   console.log("write-suc", res);                   },                 fail(res) {                   console.log(res);                   //发送开门指令失败时提示                   that.openDoorFail(deviceId);                 }               })

因为只有一个if中需要请求接口，所以不希望将wx.writeBLECharacteristicValue加入到promise.then中，有能么办法能让这段代码同步执行吗？