Can you imagine if every employer had to compute your pay on the last minute of the year and hand out those paychecks as you say Happy New Year ? What a silly mess that would be... so you are taxed in the year you received the paycheck not in the year you earned it.
When you work at the end of the year and the pay period goes into the next tax year and you are paid in the next tax year then you will get a W-2 for that pay in the next tax year.
