Estrutura atual das minhas promises

example.js

const create = (userUID, customerObj) => {
	return new Promise((resolve, reject) => {
		const ref = database.ref('user_data').child(userUID).child('customers').push()
		const key = ref.key;
		ref.set(customerObj)
		.then(() => {
			resolve(key)
		})
		.catch(e => {
			reject(e)
		})
	})
}