An event fired when the port has disconnected from the device.
Examples
Opening a port
Before communicating on a serial port it must be opened. Opening the port allows the site to specify the necessary parameters that control how data is transmitted and received. Developers should check the documentation for the device they are connecting to for the appropriate parameters.
js
await port.open({baudRate:9600/* pick your baud rate */});
Once the Promise returned by open() resolves the readable and writable attributes can be accessed to get the ReadableStream and WritableStream instances for receiving data from and sending data to the connected device.
Reading data from a port
The following example shows how to read data from a port. The outer loop handles non-fatal errors, creating a new reader until a fatal error is encountered and readable becomes null.
js
while(port.readable){const reader = port.readable.getReader();try{while(true){const{ value, done }=await reader.read();if(done){// |reader| has been canceled.break;}// Do something with |value|…}}catch(error){// Handle |error|…}finally{
reader.releaseLock();}}
Writing data to a port
The following example shows how to write a string to a port. A TextEncoder converts the string to a Uint8Array before transmission.