4. run() 函数及 drivers

上一节中，逻辑和外部环境的绑定我们是手动完成的：

const sink = main();
DOMEffect(sink.DOM);
consoleLogEffect(sink.Log);

现在，我们给定一个逻辑和外部环境的映射关系：

const effects = {
  DOM: DOMEffect,
  Log: consoleLogEffect
};

就可以通过定义一个 run() 方法自动完成逻辑和外部对象的绑定：

function run(main, effects) {
  const sink = main;
  Object.keys(effects).forEach(key => {
      effects[key](sink[key]);
  });
}

driver（驱动）是沟通硬件和软件的桥梁，有中介的意味，因此，把 effects 对象命名为 drivers 更加贴切。drivers[logic] 的值就表述了逻辑 logic 对应的外部对象：

function main() {
  return {
    DOM: Rx.Observable.timer(0, 1000)
      .map(i => `Seconds Elapsed ${i}`),
    Log: Rx.Observable.timer(0, 2000)
      .map(i => 2 * i)
  };
}

function DOMDriver(text$) {
  text$.subscribe(text => {
    $app = document.querySelector('#app');
    $app.textContent = text;
  });
}

function consoleLogDriver(msg$) {
  msg$.subscribe(msg => {
    console.log(msg);
  });
}

const drivers = {
  DOM: DOMDriver,
  Log: consoleLogDriver
};

function run(main, drivers) {
  const sink = main();
  Object.keys(drivers).forEach(key => {
    drivers[key](sink[key])
  });
}

run(main, drivers);
const sink = main();
DOMDriver(sink.DOM);
consoleLogDriver(sink.Log);

查看示例