CloseEvent: wasClean property

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since July 2015.

Note: This feature is available in Web Workers.

The wasClean read-only property of the CloseEvent interface returns true if the connection closed cleanly.

A boolean value. True if the connection closed cleanly, false otherwise.

The following example prints the value of wasClean to the console.

WebSocket.onclose = (event) => {
  console.log(event.wasClean);
};

Specification
WebSockets Standard # ref-for-dom-closeevent-wasclean②

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