Now that transform streams are supported in Chrome, Safari, and Firefox, they're finally ready for prime time!
The Streams API lets you break down a resource that you want to receive, send, or transform into small chunks, and then process these chunks bit by bit. Recently, Firefox 102
started to support TransformStream
,
which means TransformStream
is now
finally usable across browsers. Transform streams allow you to pipe from a
ReadableStream
to a
WritableStream
, executing a
transformation on the chunks, or consume the transformed result directly,
as shown in the following example.
class UpperCaseTransformStream {
constructor() {
return new TransformStream({
transform(chunk, controller) {
controller.enqueue(chunk.toUpperCase());
},
});
}
}
button.addEventListener('click', async () => {
const response = await fetch('/script.js');
const readableStream = response.body
.pipeThrough(new TextDecoderStream())
.pipeThrough(new UpperCaseTransformStream());
const reader = readableStream.getReader();
pre.textContent = '';
while (true) {
const { done, value } = await reader.read();
if (done) {
break;
}
pre.textContent += value;
}
});