'use strict';

const createTransform = () =>

new TransformStream({

start() {

// initialization

},

async transform(chunk, controller) {

const data = await chunk;

if (data === null) {

controller.terminate();

} else {

controller.enqueue(data.length);

}

},

flush() {

// finalization

},

});

const createWritable = () => {

const chunks = [];

const writableStream = new WritableStream({

write(chunk) {

console.log(`Value: ${chunk}`);

chunks.push(chunk);

},

close() {

console.log('Stream closed');

},

abort(err) {

console.log('Stream aborted');

console.error(err);

},

});

return { writableStream, chunks };

};

const main = async () => {

const url = 'https://developer.mozilla.org/';

const { body } = await fetch(url);

const transformStream = createTransform();

console.log({ transformStream });

const { writableStream, chunks } = createWritable();

await body.pipeThrough(transformStream).pipeTo(writableStream);

const total = chunks.reduce((a, b) => a + b);

console.log(`Bytes received: ${total}`);

};

main();