diff --git a/chapter2/2_4_2.ts b/chapter2/2_4_2.ts
index e69de29..2de62fb 100644
--- a/chapter2/2_4_2.ts
+++ b/chapter2/2_4_2.ts
@@ -0,0 +1,22 @@
+//对象
+
+interface paintOption {
+    shape: "circle" | "square";
+    xPos?: number;
+    yPos?: number;
+}
+
+function paintShape({ shape, xPos = 0, yPos = 0 }: paintOption) {
+    console.log(shape, xPos, yPos);
+}
+
+paintShape({ shape: "circle", xPos: 100, yPos: 100 });
+paintShape({ shape: "circle" });
+paintShape({ shape: "square", yPos: 100 });
+
+//泛型定义类型
+interface Box<T> {
+    content: T
+}
+let myBox: Box<string> = { content: "hello" };
+
diff --git a/chapter2/2_5.ts b/chapter2/2_5_1.ts
similarity index 100%
rename from chapter2/2_5.ts
rename to chapter2/2_5_1.ts
diff --git a/chapter2/2_5_2.ts b/chapter2/2_5_2.ts
new file mode 100644
index 0000000..0da8977
--- /dev/null
+++ b/chapter2/2_5_2.ts
@@ -0,0 +1,57 @@
+//泛型
+
+//keyof
+//一个泛型参数来约束另一个泛型参数 如下面，我们约束 Key得是T的属性之一
+function getProperty<T, Key extends keyof T>(obj: T, keyName: Key) {
+    return obj[keyName];
+}
+
+let user = {
+    name: "Tom",
+    age: 12
+}
+console.log(getProperty(user, "name")); //Tom
+
+//泛型引入构造函数
+class User {
+    name = "Tom";
+    age = 12;
+    constructor() {
+    }
+    sayHello() {
+        console.log("hello", this.name);
+    }
+}
+
+function create<T>(con: new () => T): T {
+    return new con();
+}
+
+create(User).sayHello();
+
+
+//索引类型
+type Person = { age: number, name: string, alive: boolean }
+type KSet = keyof Person;  //"age"|"name"|"alive"
+type Age = Person["age"];
+type ValueSet = Person[KSet]; //number | string | boolean  Person[keyof Person]
+
+let a: Age = 12;
+let b: KSet = "age";
+let c: ValueSet = true;
+
+
+const MyArray = [
+    { name: "Alice", age: 15 },
+    { name: "Bob", age: 23 },
+    { name: "Eve", age: 38 },
+];
+
+type Person2 = typeof MyArray[number];
+let d: Person2 = {
+    name: "Hello",
+    age: 15
+}
+
+
+
diff --git a/chapter3/3_1.ts b/chapter3/3_1.ts
new file mode 100644
index 0000000..a0bc5fe
--- /dev/null
+++ b/chapter3/3_1.ts
@@ -0,0 +1,80 @@
+// 条件类型
+//ts的条件类型就是可以判断一个类型是否继承自另一个类型  但这个三元表达式只能返回类型，也即赋值给type 
+//  SomeType extends OtherType ? TrueType : FalseType;
+
+class Animal300 {
+
+}
+class Dog extends Animal300 {
+
+}
+
+type example = Dog extends Animal300 ? number : string;
+
+//不行
+// let a:example = "123"
+//可以
+let a: example = 123;
+
+//看一个更复杂的例子
+interface IdLabel {
+    id: number;
+}
+interface NameLabel {
+    name: string;
+}
+//与泛型一起用  可以看到ts的类型系统很复杂
+type NameOrId<T extends number | string> = T extends number ? IdLabel : NameLabel;
+function createLabel<T extends number | string>(idOrName: T): NameOrId<T> {
+    if (typeof idOrName === 'number') {
+        return {
+            id: idOrName
+        } as NameOrId<T>
+    } else {
+        return {
+            name: idOrName
+        } as NameOrId<T>
+    }
+}
+
+let result1: NameLabel = createLabel("hello");
+let result2: IdLabel = createLabel(11);
+
+//与泛型一起 做类型约束
+//如下代表：如果泛型T包含属性message，则MessageOf代表T["message"]的类型，否则MessageOf代表never
+type MessageOf<T> = T extends { message: unknown } ? T["message"] : never;
+//如：
+interface User300 {
+    name: string;
+    length: number;
+    message: string
+}
+interface User301 {
+    name: string;
+    length: number;
+}
+//其中就是string
+let str: MessageOf<User300> = "hello";
+//下面就不能将string赋值给never
+// let neverX: MessageOf<User301> = "11";
+
+//再看个例子，如果类型T是数组，则Flatten是数组元素类型，否则Flatten是T本身类型
+type Flatten<T> = T extends any[] ? T[number] : T;
+let userArray = [
+    { name: "hello", age: 123 },
+    { name: "hello2", age: 1234 },
+    { name: "hello3", age: 12345 }
+]
+let user: Flatten<typeof userArray> = {
+    name: "hello",
+    age: 123
+}
+let ageXX: Flatten<number> = 123;
+
+
+//将T扩展成数组
+type toArray<T> = T extends any ? T[] : never;
+type strArrayOrNumberArray = toArray<string | number>; //string[] | number[]
+
+let strArray: strArrayOrNumberArray = ["1234", "2345", "3456"];
+let numberArray: strArrayOrNumberArray = [1234, 2345, 3456];
\ No newline at end of file
diff --git a/chapter3/3_2.ts b/chapter3/3_2.ts
new file mode 100644
index 0000000..f2dc2b2
--- /dev/null
+++ b/chapter3/3_2.ts
@@ -0,0 +1,85 @@
+//映射类型
+//在说映射类型前 再聊下索引签名 在ts中核心解决的是如何描述一个数据结构的类型
+//索引签名解决的是 对于一个尚未声明的结构，我们如何规范这个结构，假设我现在有一个user对象，如何规范这个user呢？
+
+type UserIndex = {
+    [key: string]: string
+}
+//如上 我们规定结构UserIndex必须是key是string value也是string类型，比如：
+let user320: UserIndex = {
+    name: "Tom"
+}
+//上面这个是ok的，但如果我们写成：
+// let user321: UserIndex = {
+//     age: 12
+// }
+// 就不行
+//我们可以通过索引类型拿到一个已知对象的value类型:
+let user302 = {
+    name: "hello",
+    age: 123,
+    alive: true
+}
+//此时User302Type就是 string | number | boolean
+type User302Type = (typeof user302)["name" | "age" | "alive"];
+//索引类型的核心是通过索引拿到value的类型，还可以通过keyof这样 这种情况与上面的结果一样 keyof就是上面的"name" | "age" | "alive"
+type User302Type1 = (typeof user302)[keyof typeof user302];
+
+//索引类型+泛型 = 映射类型
+type OptionsFlags<T> = {
+    [Property in keyof T]: boolean;
+}
+//我们分析下上例：
+//keyof T是拿到类型T的每个属性 property就是上面的每个属性 并将每个属性变为boolean，举个例子：
+interface User303 {
+    name: string,
+    age: number
+}
+//上面我们定义了name和age两个属性，分别是string和number，但通过OptionsFlags一转化 
+//得到的新属性其实是：{name:boolean,age:boolean} 将上面这些属性的类型都改为了boolean 属性名保留，类型被替换了
+type User303Flag = OptionsFlags<User303>;
+let user303FlagObj: User303Flag = {
+    name: true,
+    age: false
+}
+//所以映射修改器就是将原来Type内属性的类型改为其他类型
+//同时映射属性还可以修改可选性?与可变性readOnly 改变的意思是可以添加或者删除 也即添加上可选性/可变性 或者删除可选性 可变性 https://www.typescriptlang.org/docs/handbook/2/mapped-types.html
+type OptionsFlags2<T> = {
+    [property in keyof T]?: T[property];
+}
+//可以不写任何属性，因为都是可选
+let user303FlagObj2: OptionsFlags2<User303> = {
+}
+
+//除了可以更改value类型，还可以通过as 更改属性名字：
+//Capitalize是ts中的类型操作符，用于在类型层面将字符串类型的首字母大写 如：type small = "hello"  type CapitalizedSmall = Capitalize<Small>;  // 类型为 'Hello'
+//而string&property是明确告诉Capitalize我的property是string类型的
+type ToGetter<T> = {
+    [property in keyof T as `get${Capitalize<string & property>}`]: () => T[property];
+}
+
+interface User304 {
+    name: string,
+    age: number
+}
+type UserGetter = ToGetter<User304>;
+let userGetterObj: UserGetter = {
+    getName() {
+        return "hello";
+    },
+    getAge() {
+        return 12;
+    }
+}
+
+//Exclude操作符可以删除某些属性
+type ExcludeType<T, V> = {
+    [property in keyof T as Exclude<property, V>]: T[property]
+}
+
+//删除name属性 这个还是挺普遍用的，可以传入两个参数，来删除指定类型的指定属性
+type ExcludeUser304 = ExcludeType<User304, "name">;
+let excludeUser304Obj: ExcludeUser304 = {
+    age: 12,
+}
+
diff --git a/chapter4/4_1.ts b/chapter4/4_1.ts
new file mode 100644
index 0000000..d5ba362
--- /dev/null
+++ b/chapter4/4_1.ts
@@ -0,0 +1,16 @@
+interface User400 {
+    name: string,
+    sayIt: () => void;
+}
+
+//函数加了this挺麻烦的，有些类似于go中的方法，函数绑了对象
+//这种时候只能通过对象.函数名()调用
+function sayHello(this: User400) {
+    console.log(this.name);
+}
+
+let user400: User400 = {
+    name: "Tom",
+    sayIt: sayHello
+}
+user400.sayIt();
diff --git a/test/test.ts b/test/test.ts
new file mode 100644
index 0000000..b766b77
--- /dev/null
+++ b/test/test.ts
@@ -0,0 +1,82 @@
+interface User {
+    login: string;
+    id: number;
+    node_id: string;
+    avatar_url: string;
+    gravatar_id: string;
+    url: string;
+    html_url: string;
+    followers_url: string;
+    following_url: string;
+    gists_url: string;
+    starred_url: string;
+    subscriptions_url: string;
+    organizations_url: string;
+    repos_url: string;
+    events_url: string;
+    received_events_url: string;
+    type: string;
+    site_admin: boolean;
+    name: string;
+    company: string;
+    blog: string;
+    location: string;
+    email: null;
+    hireable: null;
+    bio: string;
+    twitter_username: null;
+    public_repos: number;
+    public_gists: number;
+    followers: number;
+    following: number;
+    created_at: string;
+    updated_at: string;
+}
+
+
+async function test() {
+    let url = 'https://api.github.com/users/coderzoe';
+    let response = await fetch(url)
+    let user: User = await response.json(); //通过js的强类型
+    console.log(user.login);
+}
+
+
+async function process() {
+    let url: string = "https://api.github.com/repos/javascript-tutorial/en.javascript.info/commits?per_page=100";
+    const response = await fetch(url);
+    const reader = response.body!.getReader();
+    // console.log('aaa', response.headers.get("Content-Length"));
+    console.log('aaa', response.headers.get("Transfer-Encoding"));
+    const totalLength = Number(response.headers.get("Content-Length"));
+    let received = 0;
+    while (true) {
+        const { done, value } = await reader!.read();
+        if (done) {
+            console.log(`总共需要接收${totalLength},现在接收${received}`);
+            break;
+        }
+        received += value.length;
+        console.log(`总共需要接收${totalLength},现在接收${received}`);
+    }
+}
+
+
+async function abort() {
+    let controller = new AbortController();
+    controller.signal.addEventListener("abort", event => {
+        console.log("任务停止");
+    });
+    let url = "https://api.github.com/repos/javascript-tutorial/en.javascript.info/commits?per_page=100";
+    let response = await fetch(url, {
+        signal: controller.signal
+    });
+    setTimeout(() => {
+        //调用终止操作
+        controller.abort();
+    }, 100);
+
+}
+test()
+process();
+abort();
\ No newline at end of file