订阅发布模式

pubsub.js

let subscribers = {};

module.exports = {
    publish(event, data) {
        if(subscribers[event])
          subscribers[event].forEach(cb => cb(data));
    },
    subscribe(event, callback) {
      if (!subscribers[event]) {
          subscribers[event] = [];
      }
      subscribers[event].push(callback)

      let index = subscribers[event].length - 1;
      return {
          unsubscribe() {
              subscribers[event].splice(index, 1);
          }
      };
    }
};

moduleA.js

const pubSub = require("./pubsub");
module.exports = {
    publishEvent() {
        pubSub.publish("anEvent", {
          msg: "TOP SECRET DATA"
        });
    }
};

moduleB.js

const pubSub = require("./pubsub");

let subscription = pubSub.subscribe("anEvent", data => {
  console.log(`"anEvent", was published with this data: "${data.msg}"`);
  subscription.unsubscribe();
});

index.js

const moduleA = require("./moduleA");
require("./moduleB");

moduleA.publishEvent();
moduleA.publishEvent();

参考目录

JavaScript Design Patterns Part 2: The Publisher/Subscriber Pattern