One of the men had been to the store earlier that day and robbed vape liquid, police said.
They returned late at night and forced their way in before charging the worker, “punching and stomping on him and throwing shop furniture at him forcefully”, the force added.
The victim needed medical treatment.
The till was damaged and more than £600 of stock was taken.
A video of the “unprovoked attack” filmed by one of the men was posted on Snapchat and was used as evidence against them, Det Con Lucy Williams said.
“Their actions on that day were completely out of order,” she said, while praising the victim’s bravery for coming forward.
The sentences would hopefully “provide some reassurance to shop workers that your safety and protection is important to us”, she said.
