How do I convert base64 string image to blob in React Native? - react-native

Question

I am trying to using React-Native-Camera to capture an image and upload to the server, the captured response only provide base64 image and relative uri path to the system's cache. I used to turn the image to a blob in websites using packages like blob-util, which doesn't work on React-native.
As I was searching around I see that most people are uploading the base64 strings directly to the server, but I can't find anything about blob, how can I get a blob from base64 image string?

Answer 1

I have a function in my project to convert image to a blob. Here it is. 1st function is to handle the camera. 2nd fuction is to create a blob and a image name.
addPicture = () => {
ImagePicker.showImagePicker({ title: "Pick an Image", maxWidth: 800, maxHeight: 600 }, res => {
if (res.didCancel) {
console.log("User cancelled!");
} else if (res.error) {
console.log("Error", res.error);
} else {
this.updateProfilePicture(res.uri)
}
});
}
This addPicture is used to launch the image picker. In above function, res means the output, that comes from showImagePicker. I had to pass the uri prop of the result(res.uri) to below function, in order to create the blob file
In below function, I wanted to name the image with userId. You can use anything you like.
updateProfilePicture = async (uri) => {
var that = this;
var userId = this.state.user.uid
var re = /(?:\.([^.]+))?$/;
var ext = re.exec(uri)[1];
this.setState({
currentFileType: ext
});
const blob = await new Promise((resolve, reject) => {
const xhr = new XMLHttpRequest();
xhr.onload = function () {
resolve(xhr.response);
};
xhr.onerror = function (e) {
console.log(e);
reject(new TypeError('Network request failed'));
};
xhr.responseType = 'blob';
xhr.open('GET', uri, true);
xhr.send(null);
});
var filePath = userId + '.' + that.state.currentFileType;
}
There are some other codes in above function, which are using to uplad the image to firebase storage. I did not include those codes.