universal-router/src/UniversalRouter.js

Isomorphic router for JavaScript web applications

/**
 * Universal Router (https://www.kriasoft.com/universal-router/)
 *
 * Copyright © 2015-present Kriasoft, LLC. All rights reserved.
 *
 * This source code is licensed under the Apache 2.0 license found in the
 * LICENSE.txt file in the root directory of this source tree.
 */

import pathToRegexp from 'path-to-regexp';
import matchPath from './matchPath';
import matchRoute from './matchRoute';
import resolveRoute from './resolveRoute';

function isChildRoute(parentRoute, childRoute) {
  let route = childRoute;
  while (route) {
    route = route.parent;
    if (route === parentRoute) {
      return true;
    }
  }
  return false;
}

class UniversalRouter {
  constructor(routes, options = {}) {
    if (Object(routes) !== routes) {
      throw new TypeError('Invalid routes');
    }

    this.baseUrl = options.baseUrl || '';
    this.resolveRoute = options.resolveRoute || resolveRoute;
    this.context = Object.assign({ router: this }, options.context);
    this.root = Array.isArray(routes) ? { path: '', children: routes, parent: null } : routes;
    this.root.parent = null;
  }

  resolve(pathnameOrContext) {
    const context = Object.assign(
      {},
      this.context,
      typeof pathnameOrContext === 'string' ? { pathname: pathnameOrContext } : pathnameOrContext,
    );
    const match = matchRoute(
      this.root,
      this.baseUrl,
      context.pathname.substr(this.baseUrl.length),
      [],
      null,
    );
    const resolve = this.resolveRoute;
    let matches = null;
    let nextMatches = null;

    function next(resume, parent = matches.value.route, prevResult) {
      const routeToSkip = prevResult === null && matches.value.route;
      matches = nextMatches || match.next(routeToSkip);
      nextMatches = null;

      if (!resume) {
        if (matches.done || !isChildRoute(parent, matches.value.route)) {
          nextMatches = matches;
          return Promise.resolve(null);
        }
      }

      if (matches.done) {
        return Promise.reject(Object.assign(
          new Error('Page not found'),
          { context, status: 404, statusCode: 404 },
        ));
      }

      return Promise.resolve(resolve(
        Object.assign({}, context, matches.value),
        matches.value.params,
      )).then((result) => {
        if (result !== null && result !== undefined) {
          return result;
        }

        return next(resume, parent, result);
      });
    }

    context.next = next;

    return next(true, this.root);
  }
}

UniversalRouter.pathToRegexp = pathToRegexp;
UniversalRouter.matchPath = matchPath;
UniversalRouter.matchRoute = matchRoute;
UniversalRouter.resolveRoute = resolveRoute;

export default UniversalRouter;