useBackNavigation()

A hook used in react-router apps that solves common problems:

Problem 1

• Your web app has modals (under urls) which open and have the ability to be closed by an X or similar
• Your modals also have sub-routes/sub-pages which the user can navigate through, pushing to the history stack
• When you click the X, you want to close the entire modal and go back to where you opened it from, regardless of where you navigated to since opening it

function MyModal() {
    const { backUrl } = useBackNavigation();

    return (
        <dialog>
            <h1>My Modal</h1>
            <nav>
            <ul>
                <li><Link to="modal/sub-route">Sub-Route</Link></li>
                <li><Link to="modal/sub-route-2">Sub-Route 2</Link></li>
            </ul>
            </nav>
            {/* This will never change while the modal is mounted. */}
            <Link to={backUrl}>Close</Link>
        </dialog>
    );
}

function Dashboard() {
    const { createBackUrlState } = useBackNavigation();
    return (
        <div>
            <h1>Dashboard</h1>
            <Link to="modal-route" state={createBackUrlState()}>Open Modal</Link>
        </div>
    );
}

1. useBackNavigation() is used in the modal component that we want to open.
2. Entrypoints to said modal (links, buttons, useNavigate etc) use useBackNavigation() to push to location.state when they navigate i.e <Link to="modal/route" state={createBackUrlState()}>Open Modal</Link>
3. useBackNavigation() in point 1 sets the backUrl from location.state that was pushed in 2 and can now build functions that will navigate to that backUrl when triggered.
4. Closing X in the modal has something like <Link to={backUrl}>Close</Link>

Problem 2

• A user lands at your app on a modal with a closing X
• We have no previous in-app route to go back to, so we just want to go back to the root of the app

function MyModal() {
    const { backUrl } = useBackNavigation();

    return (
        <dialog>
            <h1>My Modal</h1>
            <Link to={backUrl ?? '/'}>Close</Link>
        </dialog>
    );
}

1. if backUrl is undefined, we want can fallback to a desired route.

Problem 3

• When a user clicks to go back, i.e on a "back arrow" in a header of some sort
• You want to go back to the previous route that was in the URL bar before they clicked the back arrow
• However, it might be that they landed on said route from somewhere outside the app
• We don't want to send the user back outside the app
• If we detect that a route is a "landing route" by using the useSetLandingRoute we can detect this and act accordingly.
• When the user clicks back we can do the following:
  • Is it a landing route? Go to the root of the app
  • Do we have a backUrl in the state? Go to that route
  • Otherwise, navigate(-1) on the browser history

function AppRoot() {
    useSetLandingRoute();

    return <AppRoutes />
}

function SomePageWithBackArrow() {
    const { onBack } = useBackNavigation();

    return (
        <header>
            <button type="button" onClick={onBack}>Back</button>
            <p>content...</p>
        </header>
    );
}