The cancel() method of the ReadableStream interface returns a Promise that resolves when the stream is canceled.
Cancel is used when you’ve completely finished with the stream and don’t need any more data from it, even if chunks are enqueued waiting to be read. That data is lost after cancel is called, and the stream is not readable any more. To close the stream without getting rid of enqueued chunks, use ReadableStreamDefaultController.close().
Arguments
Name
Type
Description
reason
any
An optional human-readable value that represents the reason for canceling the stream.
Return value
A promise that resolves with the value undefined when the stream is canceled.
Exceptions
Exception
Description
TypeError
Thrown the stream is locked to a reader.
Example
JavaScript
import{ ReadableStream }from'k6/experimental/streams';import{ setTimeout }from'k6/timers';exportdefaultasyncfunction(){// Define a number stream that emits numbers from 1 to 10 every secondconst stream =numbersStream();const reader = stream.getReader();while(true){const{ done, value }=await reader.read();if(done)break;if(value ===8){// Cancel the stream when the number is 8, any enqueued chunks are lostawait reader.cancel('cancelling the stream');break;}}}functionnumbersStream(){let currentNumber =0;returnnewReadableStream({start(controller){constfn=()=>{if(currentNumber <10){
controller.enqueue(++currentNumber);setTimeout(fn,1000);return;}
controller.close();};setTimeout(fn,1000);},});}