Web Streams API

3種類Streamを繋いで使う

参考

Vercelによるわかりやすい解説

Vercelによる解説

https://gyazo.com/6e0a365bb63f6f2ef0001d0147596507

code:例.ts

const decoder = new TextDecoder();

const encoder = new TextEncoder();

const readableStream = new ReadableStream({

start(controller) {

const text = "Stream me!";

controller.enqueue(encoder.encode(text)); // queueにいれる

controller.close();

},

});

const transformStream = new TransformStream({

transform(chunk, controller) {

// データを取り出して、変換して、再度queueにいれる

const text = decoder.decode(chunk);

controller.enqueue(encoder.encode(text.toUpperCase()));

},

});

const writableStream = new WritableStream({

write(chunk) {

console.log(decoder.decode(chunk)); // 取り出す

},

});

// 呼び出す

// pipeThrough, pipeToを使う

readableStream

.pipeThrough(transformStream)

.pipeTo(writableStream); // STREAM ME!

code:ts

const stream = new WritableStream(...)

async function writeData(data) {

const writer = stream.getWriter();

for (const chunk of data) {

await writer.ready; // Streamに追加で書き込んでよいかの判断

writer.write(chunk);

}

writer.close();

}