Question

我正在尝试在response => {}中使用await调用但是我在等待中得到一个错误，提示期待新行或分号。我认为该错误是由于函数的结构引起的，但是我不确定如何纠正它。

我要执行的操作是添加/更新用户的个人资料图像。当用户单击touchableOpacity缩略图时，将调用_pickImageHandler()，如果选择了图像并且响应正常，它将等待调用uploadImageToStorage函数，该函数会将图像上传到Firebase Storage。

如果uploadImageToStorage返回true，那么我想调用editProfileImage将downloadUrl添加到用户文档中。

_pickImageHandler = async () => {
    ImagePicker.showImagePicker({title: "Select Image", maxWidth: 800, maxHeight: 600},

   // I'm assuming I have to somehow adapt the below response line to fix my problem
        response => {
            if (response.didCancel) {
                console.log("User cancelled!");
                if (!response.uri) {
                    this.showToast('User profile image cannot be empty', 'ok', 'warning')
                }
            }
            else if (response.error) {
                //todo look at putting below line into toast message
                console.log("Error", response.error);
            }
            else {
                console.log("pickedImage URI: ", response.uri);
                console.log("pickedImage FileName: ", response.fileName);

                this.setState({
                    //pickedImageUri: response.uri,
                    userProfileImageUrl: response.uri,
                    imageName: response.fileName
                });
               // Im getting the error on the below line 
              // Expecting a new line or semicolon
                let didImageUploadToStorage = await this._uploadImageToStorage(response.uri, response.fileName);

                if (didImageUploadToStorage) {
                    console.log('didImageUploadToStorage', didImageUploadToStorage);
                    this.editUserProfileImage()
                }
                else {
                    console.log('didImageUploadToStorage', didImageUploadToStorage);
                }
            }
        })
};



_uploadImageToStorage = async (uri, fileName) => {
    console.log("uploadImage Triggered!");
    console.log("uri: ", uri);
    console.log("fileName: ", fileName);
    //todo add in another folder after userEvents so it will be userEvents/eventDoc.id/filename

    const storageRef = firebase.storage().ref(ref);


    await storageRef.put(uri)
        .then(snapshot => {
            console.log("Upload Success!!!!! :) ");
            console.log("downloadUrl: ", snapshot.downloadURL);
            this.setState({
                userProfileImageUrl: snapshot.downloadURL,
            });
            return true
        })
        .catch((error) => {
            console.log('FirebaseStorage upload error:', error);
            return false
        });
};



 editUserProfileImage = () => {
    console.log('editUserProfileImage FIRED!');
    console.log('editUserProfileImage text: ', this.state.userProfileImageUrl);

    if (!this.state.userProfileImageUrl.length) {
        this.showToast('Profile image URL cannot be empty', 'OK', 'danger');
        return
    }
    console.log('3 userDocExists: ', this.state.userDocExists);
    if (this.state.userDocExists) {
        console.log('docExists == true');
        this.updateFieldInDB(usersCollectionRef, 'i4Mefea0wUjHW07jEk0W', 'userProfileImageUrl', this.state.userProfileImageUrl)
    }
    else {
        console.log('docExists == false');
        this.setFieldInDB(usersCollectionRef, 'i4Mefea0wUjHW07jEk0W', 'userProfileImageUrl', this.state.userProfileImageUrl)
    }
}

有更少的函数调用来实现更好，更高效的方法。谢谢您的帮助。

Answer 1

将async添加到函数中，然后await将被识别为函数中的有效关键字（假设您使用的是支持异步函数的浏览器或正在进行编译）：

async response => {
  // ...
}

Answer 2

要使用await运算符，必须在async函数内部使用它。将您的回调更改为类似的内容即可完成工作。

async (response) => {
    // your logic
}

Answer 3

如我所见，您的代码中，回复应为async

在响应函数中调用等待

3 个答案: