Web/API/ReadableStream/pipeThrough

This is an experimental technologyCheck the Browser compatibility table carefully before using this in production.

The pipeThrough() method of the ReadableStream interface provides a chainable way of piping the current stream through a transform stream or any other writable/readable pair.

Piping a stream will generally lock it for the duration of the pipe, preventing other readers from locking it.

Syntax

var transformedStream = readableStream.pipeThrough(transformStream[, options]);

Parameters

transformStream

A TransformStream (or an object with the structure {writable, readable}) consisting of a readable stream and a writable stream working together to transform some data from one form to another. Data writen to the writable stream can be read in some transformed state by the readable stream. For example, a TextDecoder, has bytes written to it and strings read from it, while a video decoder has encoded bytes written to it and uncompressed video frames read from it.

options Optional

The options that should be used when piping to the writable stream. Available options are:

preventClose

1. If this is set to true, the source ReadableStream closing will no longer cause the destination WritableStream to be closed. The method will return a fulfilled promise once this process completes, unless an error is encountered while closing the destination in which case it will be rejected with that error.
2. preventAbort: If this is set to true, errors in the source ReadableStream will no longer abort the destination WritableStream. The method will return a promise rejected with the source’s error, or with any error that occurs during aborting the destination.
3. preventCancel: If this is set to true, errors in the destination WritableStream will no longer cancel the source ReadableStream. In this case the method will return a promise rejected with the source’s error, or with any error that occurs during canceling the source. In addition, if the destination writable stream starts out closed or closing, the source readable stream will no longer be canceled. In this case the method will return a promise rejected with an error indicating piping to a closed stream failed, or with any error that occurs during canceling the source.
4. signal: If set to an AbortSignal object, ongoing pipe operations can then be aborted via the corresponding AbortController.

Return value

The readable side of the transformStream.

Exceptions

TypeError

The writable and/or readable property of transformStream are undefined.

Examples

In the following example (see [[../../../../../../../mdn.github.io/dom-examples/streams/png-transform-stream/index|Unpack chunks of a PNG]] for the full code running live, and png-transform-stream for the source code), an image is fetched and its body retrieved as a ReadableStream. Next, we log the contents of the readable stream, use pipeThrough() to send it to a new function that creates a gray-scaled version of the stream, then log the new stream's contents too.

// Fetch the original image
fetch('png-logo.png')
// Retrieve its body as ReadableStream
.then(response => response.body)
.then(rs => logReadableStream('Fetch Response Stream', rs))
// Create a gray-scaled PNG stream out of the original
.then(body => body.pipeThrough(new PNGTransformStream()))
.then(rs => logReadableStream('PNG Chunk Stream', rs))

Specifications

Specification	Status	Comment
StreamsThe definition of 'pipeThrough()' in that specification.	Living Standard	Initial definition.

Browser compatibility

The compatibility table on 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	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
pipeThrough Experimental'	Chrome Full support 59	Edge Full support 79	Firefox No support No	IE No support No	Opera Full support 46	Safari Full support 10.1	WebView Android Full support 59	Chrome Android Full support 59	Firefox Android No support No	Opera Android Full support 43	Safari iOS Full support 10.3	Samsung Internet Android Full support 7.0

Legend

Full support  

Full support

No support  

No support

Experimental. Expect behavior to change in the future.'

Experimental. Expect behavior to change in the future.

ReadableStream.pipeThrough() by Mozilla Contributors is licensed under CC-BY-SA 2.5.