setAsyncRouteLeaveHook

export const setAsyncRouteLeaveHook = (router, route, hook)=> {
	let withinHook = false;
	let finalResult = undefined;
	let finalResultSet = false;

	router.setRouteLeaveHook(route, nextLocation => {
		withinHook = true
		if (!finalResultSet) {
			hook(nextLocation).then(result => {
				finalResult = result
				finalResultSet = true
				if (!withinHook && nextLocation) {
					router.push(nextLocation)
				}
			})
		}
		const result = finalResultSet ? finalResult : false
		withinHook = false
		finalResult = undefined
		finalResultSet = false
		return result
	});
	
};