auru / redux-unity-router

src/middleware.js

import { ACTION_PREFIX, ACTION_TYPES, HISTORY_METHODS} from './constants';
import { parsePath } from 'history';

export default ({ history, routeParser }) => ({ dispatch, getState }) => next => action => {

The parameter getState is not used and could be removed.

The parameter dispatch is not used and could be removed.

    if (action.type.indexOf(ACTION_PREFIX) === 0 && action.type !== ACTION_TYPES.LOCATION_CHANGED) {

        if (action.type === ACTION_TYPES.GO_TO_ROUTE) {
            action.type = ACTION_TYPES.PUSH;
            action.payload = routeParser(action.payload);
        }

        if ([ACTION_TYPES.PUSH, ACTION_TYPES.REPLACE].includes(action.type)) {

            action.payload = typeof action.payload === 'string' ? parsePath(action.payload) : action.payload;

            const sameLocation = history.location.pathname === action.payload.pathname
                              && history.location.search === action.payload.search
                              && history.location.hash === action.payload.hash;

            action.type = sameLocation ? ACTION_TYPES.REPLACE : action.type;
        }

        if (HISTORY_METHODS[action.type]) {
            history[HISTORY_METHODS[action.type]](action.payload);
        }

        return;
    }

    return next(action); // eslint-disable-line consistent-return
};