vstack-router/cjs/create_router.js

Universal router

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.createRouter = createRouter;

function createRouter(history, transition) {
  const listeners = new Set();
  const waiting = new Set();
  let nextLocation;
  let inProcess = false;

  function listen(listener) {
    listeners.add(listener);
    return () => {
      listeners.delete(listener);
    };
  }

  async function navigateTo(location) {
    const screen = await transition(location);

    if (screen) {
      for (const listener of listeners) {
        listener(screen, location);
      }
    }
  }

  async function processQueue() {
    if (inProcess) {
      return;
    }

    if (!nextLocation) {
      for (const resolve of waiting) {
        resolve();
      }

      waiting.clear();
      return;
    }

    const location = nextLocation;
    nextLocation = undefined;
    inProcess = true;

    try {
      await navigateTo(location);
    } catch (error) {
      console.error(error.stack);
    } finally {
      inProcess = false;
      processQueue();
    }
  }

  function waitQueue() {
    return new Promise(resolve => {
      if (inProcess) {
        waiting.add(resolve);
      } else {
        resolve();
      }
    });
  }

  history.listen(location => {
    nextLocation = location;
    processQueue();
  });
  return {
    listen,
    waitQueue
  };
}