From df2ac682181ba4fa56cbbf1254db33ae6a03c280 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E7=A7=A6=E7=A3=8A?= <qinlei@e-sscard.com>
Date: Wed, 8 Apr 2020 09:51:14 +0800
Subject: [PATCH] #9# finish map

---
 src/react/ReactChildren.js | 85 ++++++++++++++++++++++++++++++++++++--
 1 file changed, 82 insertions(+), 3 deletions(-)

diff --git a/src/react/ReactChildren.js b/src/react/ReactChildren.js
index bbc07d8..0c1be7c 100644
--- a/src/react/ReactChildren.js
+++ b/src/react/ReactChildren.js
@@ -1,8 +1,87 @@
 function mapChildren(children, func, context) {
-    //TODO实现此mapChildren方法
-    return children;
+  if (isInvalid(children)) {
+      return [];
+  }
+  let result = [];
+  traverseChildren(children, function (child, index, key, originalKey) {
+      let mapped = fn.call(context, child, index);
+      if (!isInvalid(mapped)) {
+          if (isValidElement(mapped)) {
+              var newKey = key;
+              if (!isNullOrUndef(mapped.key) && mapped.key !== originalKey) {
+                  newKey = `${mapped.key}/${key}`;
+              }
+              mapped = cloneElement(mapped, { key: newKey });
+          }
+          result.push(mapped);
+      }
+  })
+
+  return result;
+}
+
+function traverseChildren(
+    children,
+    callback,
+) {
+    if (isNullOrUndef(children)) {
+        return 0;
+    }
+
+    var key: string | undefined, mangledKey: string;
+    if (!Array.isArray(children)) {
+        // 单个孩子节点
+        if (isObject(children)) {
+            key = children.key as string;
+        }
+        mangledKey = isNullOrUndef(key) ? '.0' :`.$${key}`;
+        callback(children, 0, mangledKey, key);
+        return 1;
+    } else if (children.length) {
+        // 多个节点，通过 stack 进行非递归的数组展开
+        var count = 0;
+        var objStack = [children];
+        var idxStack = [0];
+        var keyPrefixStack = ['.'];
+        var objIndex = 0;
+        while (objIndex >= 0) {
+            var currentArray = objStack[objIndex];
+            var currentIdx = idxStack[objIndex];
+            var obj = currentArray[idxStack[objIndex]++];
+            var keyPrefix = keyPrefixStack[objIndex];
+            if (currentIdx + 1 >= currentArray.length) {
+                objStack.pop();
+                idxStack.pop();
+                keyPrefixStack.pop();
+                objIndex--;
+            }
+            if (Array.isArray(obj)) {
+                if (obj.length) {
+                    objStack.push(obj);
+                    idxStack.push(0);
+                    keyPrefixStack.push(`${keyPrefix}${currentIdx}:`)
+                    objIndex++;
+                }
+            } else {
+                if (isInvalid(obj)) {
+                    obj = null;
+                    key = undefined;
+                } else if (isObject(obj)) {
+                    key = obj.key as string;
+                } else {
+                    key = undefined;
+                }
+                mangledKey = `${keyPrefix}${isNullOrUndef(key) ? currentIdx : ('$' + key)}`
+                callback(obj, count, mangledKey, key);
+                count++;
+            }
+        }
+        return count;
+    }
+    // 空数组
+    return 0;
 }
 
 export {
     mapChildren as map,
-};
\ No newline at end of file
+};
-- 
Gitee