事件总线(发布订阅模式)

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <script>
      class EventEmitter {
        constructor() {
          this.cache = {};
        }
        on(name, fn) {
          if (this.cache[name]) {
            this.cache[name].push(fn);
          } else {
            this.cache[name] = [fn];
          }
        }
        off(name, fn) {
          let tasks = this.cache[name];
          if (tasks) {
            const index = tasks.findIndex((f) => f === fn || f.callback === fn);
            if (index >= 0) {
              tasks.splice(index, 1);
            }
          }
        }
        emit(name, once = false, ...args) {
          if (this.cache[name]) {
            let tasks = this.cache[name].slice();
            for (const fn of tasks) {
              fn(...args);
            }
            if (once) {
              delete this.cache[name];
            }
          }
        }
      }

      let eb = new EventEmitter();
      let f1 = function (name, age) {
        console.log(name + "f1 " + age);
      };
      let f2 = function (name, age) {
        console.log(name + "f2 " + age);
      };
      eb.on('aaa',f1)
      eb.off('aaa',f1)
      eb.on('aaa',f1)
      eb.on('aaa',f2)
      eb.on('bbb',f2)
      eb.emit('aaa',false,'hehe',12)
    </script>
  </body>
</html>
上一篇:k8s集群学习环境搭建


下一篇:【无人机】【2019.08】自主式无人机与环境物理交互的设计