node-modbus-serial Modbus/TCP: If the connection is broken, an unhandled promise rejection error is generated, and it can't be caught

Modbus/TCP: If the connection is broken, an unhandled promise rejection error is generated, and it can't be caught

Open ryangriggs opened this issue 4 years ago • 4 comments

If I disconnect the modbus/tcp device from the network, to test what happens, I am getting the following error:

(node:25171) UnhandledPromiseRejectionWarning: Error: TCP Connection Timed Out at Socket. (/home/pi/vision/node_modules/modbus-serial/ports/tcpport.js:111:24) at Socket.emit (events.js:315:20) at Socket._onTimeout (net.js:483:8) at listOnTimeout (internal/timers.js:554:17) at processTimers (internal/timers.js:497:7) (node:25171) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag --unhandled-rejections=strict (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 2041679)

This error seems to be un-catchable within my code, no matter where I add a try/catch block or promise .catch() statement, this error is still thrown.

Expected behavior: I should be able to catch and handle this error to avoid the unhandled promise rejection warning.