diff --git a/.babelrc b/.babelrc
index 7917da6..3a458b6 100644
--- a/.babelrc
+++ b/.babelrc
@@ -1,4 +1,4 @@
 {
-  "presets": [ "@babel/env" ],
+  "presets": [ "@babel/preset-env" ],
   "plugins": [ "version" ]
 }
diff --git a/README.md b/README.md
index 497fb82..fcd173f 100644
--- a/README.md
+++ b/README.md
@@ -35,10 +35,10 @@ ee.off('click');
 Simple and similar with `event-emitter`.
 
 
- - **on**(eventName: string, callback: Function): listen an event.
- - **once**(eventName: string, callback: Function): listen a event only once.
- - **fire**(eventName: string, ...parameters: any[]): emit / trigger an event with parameters.
- - **off**(eventName?: string, callback?: Function): unsubscribe an event.
+ - **on(eventName: string, callback: Function)**: listen an event.
+ - **once(eventName: string, callback: Function)**: listen a event only once.
+ - **fire(eventName: string, ...parameters: any[])**: emit / trigger an event with parameters.
+ - **off(eventName?: string, callback?: Function)**: unsubscribe an event.
 
 
 
diff --git a/package.json b/package.json
index 8a990f7..7e1e8cb 100644
--- a/package.json
+++ b/package.json
@@ -30,7 +30,6 @@
     "@babel/core": "^7.2.2",
     "@babel/preset-env": "^7.2.3",
     "@types/jest": "^23.3.10",
-    "babel-cli": "^6.26.0",
     "babel-plugin-version": "^0.2.3",
     "jest": "^23.6.0",
     "rimraf": "^2.6.2",
diff --git a/src/index.ts b/src/index.ts
index 2012339..447121b 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -1,5 +1,8 @@
 /**
  * mini (~500 b) version for event-emitter.
+ *
+ * Created by hustcc on 2018/12/31
+ * Contract: vip@hust.edu.cn
  */
 
 export interface Listener {
@@ -14,9 +17,9 @@ export interface EventsType {
 /**
  * const ee = new OnFire();
  *
- * ee.on('click', () => {});
+ * ee.on('click', (...values) => {});
  *
- * ee.on('mouseover', () => {});
+ * ee.on('mouseover', (...values) => {});
  *
  * ee.emit('click', 1, 2, 3);
  * ee.fire('mouseover', {}); // same with emit
@@ -48,7 +51,9 @@ export default class OnFire {
   fire(eventName: string, ...params: any[]) {
     const listeners = this.es[eventName] || [];
 
-    for (let i = 0; i < listeners.length; i ++) {
+    let l = listeners.length;
+
+    for (let i = 0; i < l; i ++) {
       const { cb, once } = listeners[i];
 
       cb.apply(this, params);
@@ -56,6 +61,7 @@ export default class OnFire {
       if (once) {
         listeners.splice(i, 1);
         i --;
+        l --;
       }
     }
   }
@@ -71,10 +77,12 @@ export default class OnFire {
       } else {
         const listeners = this.es[eventName] || [];
         // clean the event and listener
-        for (let i = 0; i < listeners.length; i ++) {
+        let l = listeners.length;
+        for (let i = 0; i < l; i ++) {
           if (listeners[i].cb === cb) {
             listeners.splice(i, 1);
             i --;
+            l --;
           }
         }
       }