问题：小程序上传文件后我需要后端返回的一个值，但这个值总是在最后面导致需要这个值的方法总是报错，打印测试后发现这它是异步的。但直接使用 await来等待也不行。 

uploadImg.wxml

<view class="upload-wrap"><view class="list-wrap"><view class="item" wx:for="{{fileList}}" wx:key="index" wx:for-index="index" wx:for-item="item"><image class="file" src="{{item.url}}" data-url="{{item.url}}" bindtap="viewImage"></image><view wx:if="{{!disabled}}" class="icon-delete" data-index="{{index}}" bindtap="delFile"><image class="icon-delete" src="/images/common/icon-delete.png" mode="widthFix"></image></view></view><view wx:if="{{!disabled && fileList.length<maxCount}}" class="add-wrap" bindtap="chooseFile"><image class="icon-camera" src="/images/common/icon-camera.png" mode="widthFix"></image></view></view>
</view>

uploadImg.js

const app = getApp();
Component({properties: {pageFileList: {optionalTypes: [Array, String],value: () => {return []},observer: function (newValue, oldValue) {let list;if (!newValue) {list = [];} else if (typeof newValue == 'string') {list = JSON.parse(newValue);}this.setData({fileList: list})}},disabled: {type: Boolean,default: false},maxSize: {type: Number,value: 5242880, // 5M},maxCount: {type: Number,value: 9,},category: {type: String,value: 'Personal', // 1:Personal，2:Article，3:Meeting},name: {type: String,value: 'Image'},// 文件类型fileType: {type: Number,value: 1, // 1:Image，2:Video，3:Excel，4:PDF文件},},data: {fileList: [],},methods: {// 选择图片chooseFile() {let choseImgCount;let fileListLen = this.data.fileList.length;let maxCount = this.data.maxCount;// 计算每次可上传的文件数量if (fileListLen == maxCount) {choseImgCount = 0;} else if (maxCount - fileListLen > 9) {choseImgCount = 9;} else {choseImgCount = maxCount - fileListLen;}wx.chooseImage({count: choseImgCount,sizeType: ['original', 'compressed'], //可以指定是原图还是压缩图，默认二者都有sourceType: ['album', 'camera'], // 选择图片的来源success: (res) => {// 限制最大文件体积let overSizeIndex = res.tempFiles.findIndex(v => v.size > this.data.maxSize);if (overSizeIndex > -1) {let msg = "";if (res.tempFiles.length > 1) {msg = "第" + (overSizeIndex + 1) + "个文件已经超过了最大文件限制："} else {msg = "该文件已经超过了最大文件限制："}app.alert.show(msg + (this.data.maxSize / 1024 / 1024).toFixed(0) + "M，请重新上传~");return;}this.uploadFile(res.tempFilePaths);}});},// 上传图片async uploadFile(tempFilePaths) {wx.showLoading({title: '上传中...',mask: true})for (let i = 0; i < tempFilePaths.length; i++) {await this.uploadFileHandler(tempFilePaths, i);if (i == tempFilePaths.length - 1) {this.triggerEvent("uploadFiles", { list: this.data.fileList, name: this.data.name });wx.showToast({title: '上传成功',icon: 'none',duration,})}}},uploadFileHandler(tempFilePaths, i) {let self = this;let fileList = self.data.fileList;return new Promise((resolve, reject) => {wx.uploadFile({url: app.siteinfo.apiUrl + '', // 需要用HTTPS，同时在微信公众平台后台添加服务器地址filePath: tempFilePaths[i], // 上传的文件本地地址name: 'file', // 服务器定义的Key值header: {'content-type': 'multipart/form-data','cookie': wx.getStorageSync('cookie')},formData: {uploadDir: self.data.category,fileType: self.data.fileType,},success: function (res) {wx.hideLoading()if (res.statusCode == 200) {let result = JSON.parse(res.data);if (result.status) {let list = [{ name: self.data.name, url: result.data.fileurl }];fileList = fileList.concat(list);self.setData({ fileList });resolve();} else {app.alert.show(result.errmsg, reject(result.errmsg));}} else {app.alert.show('状态：' + res.statusCode + '，提示：' + res.errMsg, reject(res.errMsg));}},fail: function (err) {wx.hideLoading()app.alert.show(err.errMsg, reject(err.errMsg));}});})},// 删除图片delFile(e) {wx.showModal({title: '提示',content: '确定要删除吗？',success: res => {if (res.confirm) {let fileList = this.data.fileList;fileList.splice(parseInt(e.currentTarget.dataset.index), 1);this.setData({ fileList })this.triggerEvent("uploadFiles", {list: fileList,name: this.data.name});wx.showToast({title: '删除成功',icon: 'success',duration: 2000})}}})},// 预览图片viewImage(e) {let urls = this.data.fileList.map(item => { return item.url });wx.previewImage({current: e.currentTarget.dataset.url,urls});},}
})

uploadImg.less

.upload-wrap {.list-wrap {display: flex;flex-wrap: wrap;.item {position: relative;width: 188rpx;height: 188rpx;margin-top: 40rpx;margin-right: calc(~"(100% - 564rpx) / 3");.file {width: 100%;height: 100%;vertical-align: middle;border-radius: 8rpx;}.icon-delete {width: 40rpx;position: absolute;right: -10rpx;top: -10rpx;}}}.add-wrap {display: flex;align-items: center;justify-content: center;flex-direction: column;width: 188rpx;height: 188rpx;margin-top: 40rpx;border: 1px dashed #979797;border-radius: 8rpx;background-color: #f9fafb;text-align: center;.icon-camera {width: 50rpx;height: 46rpx;pointer-events: none;}}
}

 uploadImg.json

{"component": true,"usingComponents": {}
}

应用

<upload-img category="Personal" pageFileList="{{form.image}}" maxCount="3" disabled bind:uploadFiles="uploadFiles">
</upload-img>

 data: {form: {image: '[{"name":"Image","url":"https://wechatmp.uatwechat.com/upload/PersonalCompressed/20230614/20230614114423503.jpeg"}]',video: ''},},uploadFiles(e) {let str = "form." + e.detail.name;let list = e.detail.list;if (list.length > 0) {this.setData({[str]: JSON.stringify(e.detail.list)})} else {this.setData({[str]: '',})}},

app.alert方法封装 alert.js,然后在在app.js引入可使用

const show = (message, showCancel, successCallback = function() {}) => {wx.showModal({title: '提示',content: message,confirmColor: '#DB6276',showCancel: showCancel,success(res) {if (res.confirm) {successCallback();}}})
}module.exports = {show
}

小程序上传多张图片