How to determine if my JavaScript is running in nodejs

Question

I have a script which has some program logic. I run this script using nodejs for real-time communication between server and clients. Sometime due to some errors nodejs stops and script fails to run. This is how I run my script

nodejs myscript.js

Now in this script if I have some error (lets say some undefined variable) Nodejs stops running and throws an error

ReferenceError: abcd is not defined
at WebSocket.open (/var/nodes/myserver/myscript.js:99:54)
at WebSocket.emit (events.js:92:17)

Now how can I find out that my script stopped running because of some error?? I am sure that there is someway to achieve this. If this is not possible then I am ok to run another script (lets say watch.js) to have a track on myscript.js. But how to do this??

Thank You

nodejs myscript.js ; echo "The End."

vp_arth
– vp_arth

2016-03-17 06:32:58 +00:00
Commented Mar 17, 2016 at 6:32 — vp_arth
– vp_arth, Commented Mar 17, 2016 at 6:32
PM2 could be one tool to monitor it.

zangw
– zangw

2016-03-17 06:35:34 +00:00
Commented Mar 17, 2016 at 6:35 — zangw
– zangw, Commented Mar 17, 2016 at 6:35

gabesoft · Accepted Answer · 2016-03-17 06:33:27Z

1

A node process has an uncaughtException event which you can handle

process.on('uncaughtException', (err) => {
  console.log(`Caught exception: ${err}`);
});

See more details here https://nodejs.org/api/process.html#process_event_uncaughtexception

answered Mar 17, 2016 at 6:33

gabesoft

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2 Comments

vp_arth Over a year ago

Bad practice. Your app in undefined state, you should terminate the process in callback anyway.

gabesoft Over a year ago

Right but before you terminate you can log to console or do some other cleanup

stdob-- · Accepted Answer · 2016-03-17 08:43:27Z

0

Output stderr to log file and check it:

node myscript.js 2>>"log/`date +"%Y-%m-%d %T-%N"`.log"

answered Mar 17, 2016 at 8:43

stdob--

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