first commit

lib/index.js

@@ -1,16 +1,57 @@
 !function (root, doc) {
 
   class Delegator {
-    constructor (selector/* root选择器 */) {
-      // TODO
-    }
+    /*
+     *@param 顶级选择器（代理者）
+     */
+    constructor (selector) {
+      this.root = document.querySelector(selector);//顶级dom
+      this.delegatorEvents = {};//代理元素及事件
+      //代理逻辑
+      this.delegator = e => {        
+        let currentNode = e.target;//目标节点
+        const targetEventList = this.delegatorEvents[e.type];
+        //如果当前目标节点等于事件当前所在的节点，不再向上冒泡
+        while (currentNode !== e.currentTarget) {
+          targetEventList.forEach(target => {
+            if (currentNode.matches(target.matcher)) {
+              //开始委托并把当前目标节点的event对象传过去
+              target.callback.call(currentNode, e);
+            }
+          })
+          currentNode = currentNode.parentNode;
+        }
+      }
 
-    on (event/* 绑定事件 */, selector/* 触发事件节点对应选择器 */, fn/* 出发函数 */) {
-      // TODO
     }
-
+    /*
+     *绑定事件
+     *@param event 绑定事件类型
+     *@param selector 触发事件节点对应选择器
+     *@param fn 触发函数
+     * */
+    on (event, selector, fn) {
+      if (!this.delegatorEvents[event]) {
+        this.delegatorEvents[event] = [{
+          matcher: selector,
+          callback: fn
+        }]
+        this.root.addEventListener(event, this.delegator);
+      }else{
+        this.delegatorEvents[event].push({
+          matcher: selector,
+          callback: fn
+        })
+      }
+      return this;
+    }
+    /*
+     *移除事件
+     */
     destroy () {
-      // TODO
+      Object.keys(this.delegatorEvents).forEach(eventName => {
+        this.root.removeEventListener(eventName, this.delegator)
+      });
     }
   }