Heat up a wok or skillet over high heat, add the oil when it's heated. Add the onion, cabbage, and celery into the wok, stir fry and toss continuously until the vegetables become soft and some of them are slightly charred. Add in the noodles and stir a few times before adding the soy sauce and oyster sauce. Stir continuously to combine all the ingredients in the wok. Dish out and serve immediately.