In a large skillet or wok, heat the vegetable oil over medium heat.
Add the onion and garlic and cook until softened, about 2-3 minutes.
Add the carrots, bell pepper, and peas to the skillet. Stir-fry for 2-3 minutes until the vegetables are slightly tender.
Push the vegetables to one side of the skillet and pour the beaten eggs into the empty space. Scramble the eggs until cooked through.
Add the cooked rice, diced pineapple, soy sauce, and oyster sauce to the skillet. Stir all the ingredients together until well combined.
Cook for another 2-3 minutes, stirring occasionally, until the rice is heated through.
Season with salt and pepper to taste.
Serve hot and enjoy!