Cron-like scheduling doesn't work unless a name is specified

[Doubl3]

Internally, node-schedule reject the cron-like scheduling if no configuration name is specified.
Tests done with node-schedule 1.2.0 & 1.3.0 with no success.

I need more time to troubleshoot this use case, so if someone wants to investigate a bit more to try to fix this issue... feel free.
PR welcomed of course :)