react-elmish-router

Setup

In your types folder, create the following type definitions:

// This type enumerates all the valid pages in the application
export type Route =
    | 'HELLO'
    | 'PAGE1'
    | 'PAGE2'    
    | 'PAGE_N'
    ;

// Extend your domain state with the router state, this contains all the routing information
export type State =
    DomainState
    & RouterState<Route>;    
    
export type Action =
    // Extend your domain actions with router actions
    | DomainActions
    | RouterAction<Route>;    

Now you need to create a mapping from the set of routes, to matching urls. This uses the syntax from https://github.com/rcs/route-parser

export const routeDefinitions = {
    'HELLO': '/hello',
    'PAGE1': '/page1',
    'PAGE2': '/page/2',
    'PAGE_N': '/page/more/:pageNumber'    
};

In your elmish initialization function, need to initialize the router:

function intializer(): StateEffectPair<State, Action> {
    const [state, action] = initializeRouter<Route, Omit<DomainState, 'router'>, Action>(routeDefinitions, [{
        /* Your domain state here */
    }, Effects.none<Action>()]);

    return [state, action];
}

Finally in your reducer, you need to handle the ROUTER action type. You can of course, extend the router reduce, by handling a subset of the event types. The most useful of which is probably URL_PATHNAME_UPDATED. URL_PATHNAME_UPDATED is called on page load.

        case 'ROUTER': {
            const [nextState, nextEffects] = routerReducer(prev, action);            
            if(action.subtype === 'URL_PATHNAME_UPDATED') {
              switch(action.route) {
                case 'HELLO': // do stuff here
                case 'PAGE1': // do stuff here
                case 'PAGE2': // do stuff here
                case 'PAGE_N': // do stuff here
                case false: // no matching pages
                default: throwIfNotNever(action.route); // Should never hit the default case
              }
            } else {
              return [nextState, nextEffects];
            }
        }

Usage

React Elmish Router provides various ways to navigate between routes. You can use the effect creators, goBackEffect, goForwardEffect and navigateEffect, or dispatch navigate events using dispatchGoBack, dispatchGoForward and dispatchNavigate, or alternatively use the Link, and Back and Forward react components to dispatch events for you