Web/API/ReadableStreamDefaultController/enqueue
The enqueue()
method of the ReadableStreamDefaultController
interface enqueues a given chunk in the associated stream.
Syntax
readableStreamDefaultController.enqueue(chunk);
Parameters
- chunk
- The chunk to enqueue.
Return value
undefined
.
Exceptions
- TypeError
- The source object is not a
ReadableStreamDefaultController
.
Examples
In the following simple example, a custom ReadableStream
is created using a constructor (see our [[../../../../../../../mdn.github.io/dom-examples/streams/simple-random-stream/index|Simple random stream example]] for the full code). The start()
function generates a random string of text every second and enqueues it into the stream — see controller.enqueue(string)
. A cancel()
function is also provided to stop the generation if ReadableStream.cancel()
is called for any reason.
When a button is pressed, the generation is stopped, the stream is closed using ReadableStreamDefaultController.close()
, and another function is run, which reads the data back out of the stream.
const stream = new ReadableStream({
start(controller) {
interval = setInterval(() => {
let string = randomChars();
// Add the string to the stream
controller.enqueue(string);
// show it on the screen
let listItem = document.createElement('li');
listItem.textContent = string;
list1.appendChild(listItem);
}, 1000);
button.addEventListener('click', function() {
clearInterval(interval);
fetchStream();
controller.close();
})
},
pull(controller) {
// We don't really need a pull in this example
},
cancel() {
// This is called if the reader cancels,
// so we should stop generating strings
clearInterval(interval);
}
});
Specifications
Specification | Status | Comment |
StreamsThe definition of 'enqueue()' in that specification. | Living Standard | Initial definition. |
Browser compatibility
The compatibility table in this page is generated from structured data. If you'd like to contribute to the data, please check out https://github.com/mdn/browser-compat-data and send us a pull request.
Update compatibility data on GitHub
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
|
Chrome
? |
Edge
? |
Firefox Full support 65 Full support 65 Full support 57 Disabled' From version 57: this feature is behind the |
IE
No support No |
Opera
? |
Safari
? |
WebView Android
? |
Chrome Android
? |
Firefox Android Full support 65 Full support 65 Full support 57 Disabled' From version 57: this feature is behind the |
Opera Android
? |
Safari iOS
? |
Samsung Internet Android
? |
Legend
- Full support
- Full support
- No support
- No support
- Compatibility unknown
- Compatibility unknown
- Experimental. Expect behavior to change in the future.'
- Experimental. Expect behavior to change in the future.
- User must explicitly enable this feature.'
- User must explicitly enable this feature.
ReadableStreamDefaultController.enqueue() by Mozilla Contributors is licensed under CC-BY-SA 2.5.