array method flat flatMap pratice

Author: liguanliang

Array/array_flat_flatMap.js

@@ -0,0 +1,57 @@
+/**
+ * 递归造数据
+ * @param  {array} arr
+ * @param  {number} length
+ * @param  {number} deep
+ */
+function insertArray(arr, length, deep) {
+  let len = length;
+  if (!arr.length) {
+    while (len--) {
+      arr.push([])
+    }
+    if (!deep) {
+      arr.forEach((item) => item[0] = Math.floor(Math.random() * 10))
+    }
+  } else {
+    arr.forEach(element => {
+      insertArray(element, len, deep)
+    });
+  }
+}
+/**
+ * @param  {number} deep=0
+ * @param  {number} length=0
+ * @param  {array} result=[]
+ */
+export function createNestedArray(deep = 0, length = 0, result = []) {
+
+  const resultArr = result || [];
+
+  while (deep--) {
+    insertArray(resultArr, length, deep);
+  }
+
+  return resultArr
+}
+
+/**
+ * 
+ * @param  {} targetArr
+ * @param  {} deepth=0
+ */
+export function flat(targetArr, deepth = 0) {
+  let flatArr = targetArr.flat(deepth);
+  return flatArr;
+}
+
+export function flatMap(flatMapArr, cb) {
+  function _callback(currentValue, index, array, _this) {
+
+    return currentValue.join(',')
+  }
+  const callback = cb && typeof cb === "function" ? cb : _callback;
+  let flatMapResult = flatMapArr.flatMap(callback);
+
+  return flatMapResult;
+}

Array/index.js

@@ -2,5 +2,23 @@ import {
   lengthOperate,
   funtionLoop
 } from './lengthOperate.js';
-lengthOperate();
-funtionLoop();
+
+import {
+  flat,
+  flatMap,
+  createNestedArray
+} from "./array_flat_flatMap.js"
+
+// lengthOperate();
+// funtionLoop();
+
+const length = 3;
+const deep = 3;
+
+const targetArr = createNestedArray(deep, length);
+
+const flatResult = flat(targetArr, deep);
+console.log(flatResult, 'flatResult')
+
+const flatMapResult = flatMap(targetArr);
+console.log(flatMapResult, 'flatMapResult')

index.html

@@ -73,7 +73,7 @@
 
 <!--<script src="js/timeCounter.js"></script>-->
 
-<script src="js/index.js"></script>
+<!-- <script src="js/index.js"></script> -->
 
 <!--<script src="js/30-seconds-of-code.js"></script>-->
 
@@ -110,7 +110,7 @@
 <!-- <script src="./object/Object_defineproperty.js"></script>. -->
 
 <!-- Array -->
-<!-- <script type="module" src="./Array/index.js"></script> -->
+<script type="module" src="./Array/index.js"></script>
 
 <!-- RegExp -->
 <!-- <script type="module" src="./Reg/index.js"></script> -->