docs: update readme

README.md

@@ -26,8 +26,42 @@
 
 ### 今日原题
 
+第八题：[对一个很长的名字数组，做分片更新名字请求](https://github.com/KieSun/fucking-frontend/issues/13)
+
+```js
+/*
+ * 对一个很长的名字数组，做分片更新名字请求：
+ * 1. 分片里的更新是并行的，执行 changeName
+ * 2. 各个分片间是串行的，执行 sleep
+ * 这个函数接受三个参数，名字列表、分片数量，每次分片后的等待时间
+ * 比如：
+ * slicePostTask(['aa', 'bb', 'cc', 'dd', 'ee', 'ff', 'gg', 'hh'], 2, 2000)
+ * // => ['aa', 'bb']
+ * waiting 2s
+ * // => ['cc', 'dd']
+ * waiting 2s
+ * // => ['ee', 'ff']
+ * waiting 2s
+ * // => ['gg', 'hh']
+ */
+
+const changeName = (name) => new Promise((resolve, reject) => {
+  setTimeout(() => resolve(name), 1000)
+})
+
+const sleep = time => new Promise((resolve, reject) => {
+  setTimeout(resolve, time)
+})
+
+const slicePostTask = async (names, chunkSize, time) => {
+  // todo
+}
+```
+
 第七题：[数据排重](https://github.com/KieSun/fucking-frontend/issues/11)
 
+<details>
+
 ```js
 const dedup = (data, getKey = () => {} ) => {
   // todo
@@ -57,6 +91,8 @@ let data1 = [
 // ];
 ```
 
+</details>
+
 第六题：[实现一个 chunk 函数](https://github.com/KieSun/fucking-frontend/issues/8)
 
 <details>