From 7ac2d6fb40a176d9f54977bdb82ceb5e84290e3d Mon Sep 17 00:00:00 2001
From: dp~ <457509824@qq.com>
Date: Thu, 26 Oct 2017 17:40:33 +0800
Subject: [PATCH] =?UTF-8?q?=E7=94=9F=E6=88=90=E5=99=A8=20generator?=
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 19.generator.md | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 README.MD       |  4 +++-
 2 files changed, 49 insertions(+), 1 deletion(-)
 create mode 100644 19.generator.md

diff --git a/19.generator.md b/19.generator.md
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index 0000000..9cfaf52
--- /dev/null
+++ b/19.generator.md
@@ -0,0 +1,46 @@
+# 生成器
+> `javascript` 中的函数，都是从上到下依次执行，直到结束，生成器的函数，可以在执行中开始、暂停，并可以在以后的调用中传入另外的参数。
+
+```js
+// 关键字 `*`
+function* listColors() {
+	console.log('test');
+    // 关键字 `yield` 相当于 `return` ,但是 `ruturn` 本次执行的返回值
+    yield 'red';
+    yield 'blue';
+    yield 'green';
+}
+
+// 返回一个生成器对象 在这里不会打印 `console.log('test')` 只有在执行 `next` 的时候才会有打印
+const colors = listColors();
+// 在每次调用 `next()` 方法的过程中有点像迭代器，依次返回 `yield` 指定的返回值
+colors.next(); // {value: "red", done: false}
+colors.next(); // {value: "blue", done: false}
+colors.next(); // {value: "green", done: false}
+colors.next(); // {value: undefined, done: true}
+```
+
+### 应用
+```js
+// 使用 `Generator` 生成器 控制 `ajax` 工作流
+function ajax(url) {
+    axios.get(url).then(res => userGen.next(res.data));
+}
+
+function* steps() {
+    console.log('fetching users');
+    const users = yield ajax('https://api.github.com/users');
+    console.log(users);
+
+    console.log('fetching firstUser');
+    const firstUser = yield ajax(`https://api.github.com/users/${users[0].login}`);
+    console.log(firstUser);
+
+    console.log('fetching followers');
+    const followers = yield ajax(firstUser.followers_url);
+    console.log(followers);
+}
+
+const userGen = steps();
+userGen.next();
+```
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diff --git a/README.MD b/README.MD
index 525295f..0fe29f7 100644
--- a/README.MD
+++ b/README.MD
@@ -18,4 +18,6 @@
 * [Promise](https://github.com/dptms/es6/blob/master/14.promise-intro.md)
 * [Symbol](https://github.com/dptms/es6/blob/master/15.symbol.md)
 * [模块](https://github.com/dptms/es6/blob/master/16.modules.md)
-* [类](https://github.com/dptms/es6/blob/master/17.classes.md)
\ No newline at end of file
+* [类](https://github.com/dptms/es6/blob/master/17.classes.md)
+* [遍历器 迭代器](https://github.com/dptms/es6/blob/master/18.iterator.md)
+* [生成器](https://github.com/dptms/es6/blob/master/18.generator.md)
\ No newline at end of file