Firebase ref with pagination for firebase-server

paginateRef.js

// obj === parsed.d.b.q
const paginateRef = (ref, obj = {}) => {
	Object.entries(obj).forEach(([key, value]) => {
		switch (key) {
			case "sp": {
				ref = ref.startAt(value);
				break;
			}
			case "ep": {
				ref = ref.endAt(value);
				break;
			}
			case "i": {
				if (value === ".key") {
					ref = ref.orderByKey();
				} else if (value === ".value") {
					ref = ref.orderByValue();
				} else {
					ref = ref.orderByChild(value);
				}
				break;
			}
			case "l": {
				ref = obj.vf === "l" ? ref.limitToFirst(value) : ref.limitToLast(value);
				break;
			}
			default: {
				break;
			}
		}
	});
	return ref;
};