I was trying to use Stream api with fetch in react-native app, I implemented with the help of a great example mentioned at jeakearchibald.com . code is something similar to :-
fetch('https://html.spec.whatwg.org/').then(function(response) {
console.log('response::-', response)
var reader = response.body.getReader();
var bytesReceived = 0;
reader.read().then(function processResult(result) {
if (result.done) {
console.log("Fetch complete");
return;
}
bytesReceived += result.value.length;
console.log(`Received ${bytesReceived} bytes of data so far`);
return reader.read().then(processResult);
});
});
Stream api reference is :-
But it seems fetch implementation of react-native is little different than of browsers and it is not easy to use Stream in the same way as used on web.
There is already an unresolved issue on react-native for the same https://github.com/facebook/react-native/issues/12912
On web we can access Stream from response.body.getReader(), where response is just normal result retuned from fetch call of stream url, but in react-native there is no way we can access body and hence getReader from response of fetch call.
So to overcome this I tried to use rn-fetch-blob npm package , because it supports Streams, but that to seems to support only from locale file paths because there readStream functions doesn't seems to have support to pass Authorization and other necessary headers, so I tried to use RNFetchBlob.fetch with the remote url and necessary headers and then using readStream method from response but that always returns me there is no stream with the current response.
RNFetchBlob.fetch('GET', 'https://html.spec.whatwg.org/')
.progress((received, total) => {
console.log('progress', received / total);
})
.then((resp) => {
// const path = resp.path();
console.log('resp success:-', resp);
RNFetchBlob.fs.readStream(path, 'utf8').then((stream) => {
let data = '';
stream.open();
stream.onData((chunk) => {
data += chunk;
});
stream.onEnd(() => {
console.log('readStream::-', data);
});
// });
})
.catch((err) => {
console.log('trackAppointmentStatus::-', err);
});
I may be doing something wrong in both approaches of mine, so little guidance may help me or someone else in the future. Or I may need to find a way to do it natively with writing a bridge.
import 'react-native-polyfill-globals/auto';in the index.js file instead! – Windblown