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

The closed getter property of the WritableStreamDefaultWriter interface returns a promise that fulfills if the stream becomes closed or the writer's lock is released, or rejects if the stream errors.


var closed = writableStreamDefaultWriterInstance.closed;


A Promise.


const writableStream = new WritableStream({
  start(controller) {
  write(chunk, controller) {
  close(controller) {
  abort(err) {
}, queuingStrategy);


const writer = writableStream.getWriter();


// check if the stream is closed
writer.closed.then(() => {
  console.log('writer closed');


Specification Status Comment
The definition of 'closed' in that specification.
Living Standard Initial definition.

Browser compatibility

Update compatibility data on GitHub
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidEdge MobileFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
Basic support
Chrome Full support 59Edge Full support 16Firefox No support NoIE No support NoOpera Full support 46Safari ? WebView Android Full support 59Chrome Android Full support 59Edge Mobile No support NoFirefox Android No support NoOpera Android Full support 46Safari iOS ? Samsung Internet Android ?


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.

Document Tags and Contributors

Contributors to this page: connorshea, chrisdavidmills
Last updated by: connorshea,