The enqueue() method of the ReadableStreamDefaultController interface enqueues a given chunk in the associated stream.
ReadableStreamDefaultController.enqueue()
Syntax
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 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
Browser compatibility
| Desktop | Mobile | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Chrome | Edge | Firefox | Internet Explorer | Opera | Safari | WebView Android | Chrome Android | Firefox for Android | Opera Android | Safari on IOS | Samsung Internet | |
enqueue |
89
|
89
|
65
|
No
|
75
|
No
|
89
|
89
|
65
|
63
|
No
|
15.0
|
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https://developer.mozilla.org/en-US/docs/Web/API/ReadableStreamDefaultController/enqueue
