Transmitter and receiver

Now I trying to understand the transmitter functionality.
I would be very thankful, If you (or some one else) can add a little explanation for those functions, especially in few moments:
in sendCommand() function there is a line

var bits = (CODE & ~0b11111) | command;

what we trying to put in "bits"? If I understand correctly, this part

(CODE & ~0b11111)

always returns our "CODE" with five right zeros, what for?

In setWatch() :

socketOn = !socketOn;

we switch between 0 and 1, what for? Is there some reason for?

Thank you in advance.