pm2-logrotate-out.log content contains `undefined`

[Martii]

Since about the early part of March, 2017 this package doesn't seem to be rotating at all now. January through early part of March, 2017 did.

Log file for this month after a manual fix (removal of March and April 2017) of all affected log files (also present from March 7th forward):

undefined

... what it normally has (edited for ~ for security reasons)...

"~/.pm2/logs/app-error__2017-03-07_00-00-00.log" has been created

Config since January 2017 (used http://www.cronmaker.com/ to make the rotateInterval... rotating once a month on the first at 00:00... reconfirmed same value as of today)...

$ pm2 get pm2-logrotate
== pm2-logrotate ==
┌────────────────┬─────────────────┐
│ key            │ value           │
├────────────────┼─────────────────┤
│ max_size       │ 5M              │
│ retain         │ all             │
│ rotateInterval │ 0 0 0 1 1/1 ? * │
└────────────────┴─────────────────┘

Installation method since ~2013:

$ sudo npm install pm2 -g
$ sudo npm install pm2-logrotate -g

Latest nodejs LTS and all sub-deps updated often.

Reupdated pm2@2.4.6 today from pm2@2.4.5... same issue as last month. Rechecked manually pm2-logrotate@2.2.0 is present.

Thanks for the look.