From d1269e15861a9fd17929c96546e0a047bc379368 Mon Sep 17 00:00:00 2001
From: niduyi52 <906330048@qq.com>
Date: Fri, 22 Mar 2019 14:37:56 +0800
Subject: [PATCH] =?UTF-8?q?=E6=8F=90=E4=BA=A4exercise4?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 package-lock.json | 62 +++++++++++++++++++++++++++++++++++++++++++++++
 test/test.js      | 12 ++++++---
 2 files changed, 70 insertions(+), 4 deletions(-)
 create mode 100644 package-lock.json

diff --git a/package-lock.json b/package-lock.json
new file mode 100644
index 0000000..9a93599
--- /dev/null
+++ b/package-lock.json
@@ -0,0 +1,62 @@
+{
+  "name": "exercise4",
+  "version": "0.0.1",
+  "lockfileVersion": 1,
+  "requires": true,
+  "dependencies": {
+    "should": {
+      "version": "11.2.1",
+      "resolved": "https://registry.npmjs.org/should/-/should-11.2.1.tgz",
+      "integrity": "sha1-kPVRRVUtAc/CAGZuToGKHJZw7aI=",
+      "dev": true,
+      "requires": {
+        "should-equal": "^1.0.0",
+        "should-format": "^3.0.2",
+        "should-type": "^1.4.0",
+        "should-type-adaptors": "^1.0.1",
+        "should-util": "^1.0.0"
+      }
+    },
+    "should-equal": {
+      "version": "1.0.1",
+      "resolved": "https://registry.npmjs.org/should-equal/-/should-equal-1.0.1.tgz",
+      "integrity": "sha1-C26VFvJgGp+wuy3MNpr6HH4gCvc=",
+      "dev": true,
+      "requires": {
+        "should-type": "^1.0.0"
+      }
+    },
+    "should-format": {
+      "version": "3.0.3",
+      "resolved": "https://registry.npmjs.org/should-format/-/should-format-3.0.3.tgz",
+      "integrity": "sha1-m/yPdPo5IFxT04w01xcwPidxJPE=",
+      "dev": true,
+      "requires": {
+        "should-type": "^1.3.0",
+        "should-type-adaptors": "^1.0.1"
+      }
+    },
+    "should-type": {
+      "version": "1.4.0",
+      "resolved": "https://registry.npmjs.org/should-type/-/should-type-1.4.0.tgz",
+      "integrity": "sha1-B1bYzoRt/QmEOmlHcZ36DUz/XPM=",
+      "dev": true
+    },
+    "should-type-adaptors": {
+      "version": "1.1.0",
+      "resolved": "https://registry.npmjs.org/should-type-adaptors/-/should-type-adaptors-1.1.0.tgz",
+      "integrity": "sha512-JA4hdoLnN+kebEp2Vs8eBe9g7uy0zbRo+RMcU0EsNy+R+k049Ki+N5tT5Jagst2g7EAja+euFuoXFCa8vIklfA==",
+      "dev": true,
+      "requires": {
+        "should-type": "^1.3.0",
+        "should-util": "^1.0.0"
+      }
+    },
+    "should-util": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/should-util/-/should-util-1.0.0.tgz",
+      "integrity": "sha1-yYzaN0qmsZDfi6h8mInCtNtiAGM=",
+      "dev": true
+    }
+  }
+}
diff --git a/test/test.js b/test/test.js
index 63a72e4..0c7b240 100644
--- a/test/test.js
+++ b/test/test.js
@@ -4,7 +4,8 @@ describe('this', function () {
       say: function () {
         setTimeout(() => {
           // this 是什么？想想为什么？
-          this.should.equal(null)
+          // this指向say,箭头函数是根据当前的词法作用域来决定this。
+          this.should.equal(obj)
           done()
         }, 0)
       }
@@ -15,7 +16,8 @@ describe('this', function () {
   it('global', function () {
     function test() {
       // this 是什么？想想为什么？
-      this.should.equal(null)
+      // this指向window，这个是使用了默认绑定，绑定到了全局对象。node环境中为global
+      this.should.equal(global)
     }
     test()
   })
@@ -26,7 +28,8 @@ describe('this', function () {
         say: function () {
           function _say() {
             // this 是什么？想想为什么？
-            this.should.equal(null)
+            // bind在绑定的对象为undefined的时候，默认是绑定全局对象
+            this.should.equal(global)
           }
           return _say.bind(obj)
         }()
@@ -39,7 +42,8 @@ describe('this', function () {
       obj.say = function () {
         function _say() {
           // this 是什么？想想为什么？
-          this.should.equal(null)
+          // bind 把this指向了obj
+          this.should.equal(obj)
         }
         return _say.bind(obj)
       }()