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Important: This documentation is about an older version. It's relevant only to the release noted, many of the features and functions have been updated or replaced. Please view the current version.

Documentationbreadcrumb arrow Grafana k6breadcrumb arrow JavaScript APIbreadcrumb arrow k6/experimentalbreadcrumb arrow streamsbreadcrumb arrow ReadableStreambreadcrumb arrow getReader()
Open source

getReader()

Creates a reader and locks the stream to it. While the stream is locked, no other reader can be acquired until this one is released.

Arguments

The getReader method takes a single optional options argument, which is an object with the following properties:

NameTypeDefault valueDescription
modestringundefinedA property that specifies the type of reader to create. It currently only supports the undefined value.

Return value

A ReadableStreamDefaultReader object instance.

Example

JavaScript 
import { ReadableStream } from 'k6/experimental/streams';
import { setTimeout } from 'k6/timers';

export default async function () {
  // Define a number stream that emits numbers from 1 to 10 every second
  const stream = numbersStream();

  // We use the getReader method to create a reader and lock the stream to it
  const reader = stream.getReader();

  while (true) {
    const { done, value } = await reader.read();
    if (done) break;
    console.log(`received number ${value} from stream`);
  }
}

function numbersStream() {
  let currentNumber = 0;

  return new ReadableStream({
    start(controller) {
      const fn = () => {
        if (currentNumber < 10) {
          controller.enqueue(++currentNumber);
          setTimeout(fn, 1000);
          return;
        }

        controller.close();
      };
      setTimeout(fn, 1000);
    },
  });
}