How to make Async Await Function in React Native? - reactjs

Question

I want to create a function that is about uploading photo to Firebase Storage with react-native-fetch-blob. I'm using Redux and you can find action functions below:
My problem is that uploadImage function is not running like asynchronous. Firebase function is running before uploadImage, so application give me an error.
I think i can't make a asynchronous function. How can i fix it ?
uploadImage() function:
const uploadImage = async (imageSource, whereToUpload) => {
let imageURL = '';
const mime = 'image/jpg';
const { Blob } = RNFetchBlob.polyfill;
const { fs } = RNFetchBlob;
window.XMLHttpRequest = RNFetchBlob.polyfill.XMLHttpRequest;
window.Blob = Blob;
console.log('URI =>', imageSource.uri);
let imgUri = imageSource.uri;
let uploadBlob = null;
const imageRef = firebase.storage().ref(whereToUpload + '/' + imageSource.fileName);
const uploadUri = Platform.OS === 'ios' ? imgUri.replace('file://', '') : imgUri;
await fs.readFile(uploadUri, 'base64')
.then((data) => Blob.build(data, { type: `${mime};BASE64` }))
.then((blob) => {
uploadBlob = blob;
return imageRef.put(blob, { contentType: mime });
})
.then(() => {
uploadBlob.close();
// eslint-disable-next-line no-return-assign
return imageURL = imageRef.getDownloadURL();
})
.catch((error) => {
console.log(error);
});
return imageURL;
};
and the main action is:
export const addProjectGroup = (
myUser,
groupName,
groupDescription,
groupProfilePic,
) => dispatch => {
const groupProfileFinalPic = async () => {
let finalGroupPicture = { landscape: '' };
if (_.isEmpty(groupProfilePic.src)) {
await uploadImage(groupProfilePic, 'groupPictures').then((imageURL) => {
console.log('İŞLEM TAMAM!');
console.log('SELECTED IMAGE URL =>', imageURL);
finalGroupPicture.landscape = imageURL;
});
} else {
finalGroupPicture.landscape = groupProfilePic.src.landscape;
}
return finalGroupPicture;
};
console.log("final group profile pic =>", groupProfileFinalPic());
// Önce grubu yaratalım..
// eslint-disable-next-line prefer-destructuring
const key = firebase
.database()
.ref()
.child('groups')
.push().key;
firebase
.database()
.ref('/groups/' + key)
.set({
admin: {
email: myUser.email,
name: myUser.name,
uid: myUser.uid,
},
groupName,
groupDescription,
groupProfilePic: groupProfileFinalPic(),
projects: '',
})
.then(() => {
console.log('Groups oluşturuldu.');
})
.catch(e => {
Alert.alert('Hata', 'Beklenmedik bir hata meydana geldi.');
console.log(e.message);
});
dispatch({
type: ADD_PROJECT_GROUP,
});
};

Answer 1

You are not awaiting groupProfileFinalPic(). This should be done before creating the action you want to dispatch.
groupProfileFinalPic().then(groupProfilePic => {
return firebase
.database()
.ref("/groups/" + key)
.set({
admin: {
email: myUser.email,
name: myUser.name,
uid: myUser.uid
},
groupName,
groupDescription,
groupProfilePic,
projects: ""
})
.then(() => {
console.log("Groups oluşturuldu.");
})
.catch(e => {
Alert.alert("Hata", "Beklenmedik bir hata meydana geldi.");
console.log(e.message);
});
});
I have no clue what the last dispatch is for, you might want to do that in one of the callbacks. Your code is to verbose for an SO question, but I hope this helps anyways.

Answer 2

You are using both await and then on the same call. To use await, you can arrange it something like
const uploadImage = async (imageSource, whereToUpload) => {
...
try {
let data = await RNFS.fs.readFile(uploadUri, 'base64')
let uploadBlob = await Blob.build(data, { type: `${mime};BASE64` }))
...etc...
return finalResult
catch (e) {
// handle error
}
}