I have a http request in javascript that returns content of a file in the response. The response.body is in readablestream format. I need to get the file content in base64 format and upload in a different location. Can I know what is the best approach to convert the content to base64 string?
var url="httpurl";
var dataContent= await fetch(url);
var textContent= await dataContent.blob();
Next line is to make https call to upload a file with content in base64 string format.
I would like to know how the datacontent can be converted to base64 string.
dataContent is as in below image:

This answer has more info on how to get the response from a ReadableStream. Here's the main part with the base64 conversion included. The base64encode function is based on this
function base64encode(str: string): string {
return btoa(unescape(encodeURIComponent(str)));
}
fetch('https://jsonplaceholder.typicode.com/posts/1')
.then(function(response) {
return response.text();
}).then(function(data) {
const base64encodedData = base64encode(data);
console.log(data); // this will be a string
});