I'm using version 3.3.6 of this module. flatmap-stream was added by this commit:

[BAROTH1BOAT]

I'm using version 3.3.6 of this module. flatmap-stream was added by this commit:
dominictarr/event-stream@e316336

The new updates to the package on npm are very suspicious.

0.1.0: https://registry.npmjs.org/flatmap-stream/-/flatmap-stream-0.1.0.tgz
0.1.1: https://registry.npmjs.org/flatmap-stream/-/flatmap-stream-0.1.1.tgz
0.1.2: https://registry.npmjs.org/flatmap-stream/-/flatmap-stream-0.1.2.tgz

Regards.

Originally posted by @NewEraCracker in dominictarr/event-stream#115