perf: remove unnecessary closure

docs/proxy.md

@@ -214,24 +214,22 @@ arr[-1] // c
 利用 Proxy，可以将读取属性的操作（`get`），转变为执行某个函数，从而实现属性的链式操作。
 
 ```javascript
-var pipe = (function () {
-  return function (value) {
-    var funcStack = [];
-    var oproxy = new Proxy({} , {
-      get : function (pipeObject, fnName) {
-        if (fnName === 'get') {
-          return funcStack.reduce(function (val, fn) {
-            return fn(val);
-          },value);
-        }
-        funcStack.push(window[fnName]);
-        return oproxy;
+var pipe = function (value) {
+  var funcStack = [];
+  var oproxy = new Proxy({} , {
+    get : function (pipeObject, fnName) {
+      if (fnName === 'get') {
+        return funcStack.reduce(function (val, fn) {
+          return fn(val);
+        },value);
       }
-    });
+      funcStack.push(window[fnName]);
+      return oproxy;
+    }
+  });
 
-    return oproxy;
-  }
-}());
+  return oproxy;
+}
 
 var double = n => n * 2;
 var pow    = n => n * n;