Quick question about charging Wii U Pro controller.

Hi all. I've got a quick question about charging the Wii U Pro controller. Since the charger is USB, would it harm the controller if you try to charge it through a computer? My computer has some USB ports, and since I almost have enough money to buy one, I'm just wondering if it HAS to be charged through the Wii U.

Thanks for any help.Image may be NSFW.
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MG777