The word "either" sometimes has the opposite meaning of "too", for example:

I want a coke, too.

I don't want a coke either.

My question is about the comma before too and either. I looked up my dictionary and found there's almost always a comma before too; however, there's no comma in front of either. Could you tell me should we need to put a comma in front of either? And is it possible to leave out the comma in front of too? Please give me your opinion, thank you!
I’m citing a few dictionary examples below to show that not every sentence ending in ‘too’ has to have a comma before it and in fact, most of them (80%) do not:

I am too!

He's coming along too.

He has a Mercedes, too.

My husband likes cycling, and I do, too.

Do you know Jason too?
I'll probably go there next year too.

He's coming along too.

You can come too.

You did too!

The dog is hungry and thirsty too.
Thanks! I understand now.Emotion: smile