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In the following simple example, a previously-created custom ReadableStream is read using a ReadableStreamDefaultReader created using getReader().
(see our Simple random stream example for the full code).
Each chunk is read sequentially and output to the UI, until the stream has finished being read, at which point we return out of the recursive function and print the entire stream to another part of the UI.
jsfunction fetchStream() {
const reader = stream.getReader();
let charsReceived = 0;
// read() returns a promise that resolves
// when a value has been received
reader.read().then(function processText({ done, value }) {
// Result objects contain two properties:
// done - true if the stream has already given you all its data.
// value - some data. Always undefined when done is true.
if (done) {
console.log("Stream complete");
para.textContent = value;
return;
}
// value for fetch streams is a Uint8Array
charsReceived += value.length;
const chunk = value;
let listItem = document.createElement("li");
listItem.textContent = `Received ${charsReceived} characters so far. Current chunk = ${chunk}`;
list2.appendChild(listItem);
result += chunk;
// Read some more, and call this function again
return reader.read().then(processText);
});
}
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