Place the pork tenderloin in the bowl of a slow cooker.

In a small bowl or large measuring cup, combine pineapple juice, soy sauce, garlic, and sriracha. Pour mixture over the top of the tenderloin. Top the meat with pineapple slices.

Place the lid on the slow cooker and cook on low for 6 to 8 hours.

When the tenderloin is cooked, remove the meat from the slow cooker and allow to rest for 5 to 10 minutes.

Combine the corn starch with a small amount of cold water and stir until mixed. Pour the mixture into the bowl of the slow cooker.

Turn the slow cooker to high and whisk to combine. Allow the sauce to simmer for five minutes, whisking occasionally.

Turn the slow cooker off and allow the sauce to rest and thicken.

Slice the tenderloin and top with sauce and pineapple to serve.