From 630bbac28580dd165cee51af75eb60aabc6aaf6f Mon Sep 17 00:00:00 2001
From: justin <xief008@outlook.com>
Date: Mon, 26 Dec 2022 23:02:39 +0800
Subject: [PATCH] Add the JavaScript code (Chapter of Hashing)

---
 .../chapter_hashing/array_hash_map.js         | 129 ++++++++++++++++++
 codes/javascript/chapter_hashing/hash_map.js  |  44 ++++++
 2 files changed, 173 insertions(+)
 create mode 100644 codes/javascript/chapter_hashing/array_hash_map.js
 create mode 100644 codes/javascript/chapter_hashing/hash_map.js

diff --git a/codes/javascript/chapter_hashing/array_hash_map.js b/codes/javascript/chapter_hashing/array_hash_map.js
new file mode 100644
index 000000000..056a8007e
--- /dev/null
+++ b/codes/javascript/chapter_hashing/array_hash_map.js
@@ -0,0 +1,129 @@
+/*
+ * File: array_hash_map.js
+ * Created Time: 2022-12-26
+ * Author: Justin (xiefahit@gmail.com)
+ */
+
+/* 键值对 Number -> String */
+class Entry {
+    constructor(key, val) {
+        this.key = key;
+        this.val = val;
+    }
+}
+
+/* 基于数组简易实现的哈希表 */
+class ArrayHashMap {
+    #bucket
+    constructor() {
+        // 初始化一个长度为 100 的桶（数组）
+        this.#bucket = new Array(100).fill(null);
+    }
+
+    /* 哈希函数 */
+    #hashFunc(key) {
+        return key % 100;
+    }
+
+    /* 查询操作 */
+    get(key) {
+        let index = this.#hashFunc(key);
+        let entry = this.#bucket[index];
+        if (entry === null) return null;
+        return entry.val;
+    }
+
+    /* 添加操作 */
+    set(key, val) {
+        let index = this.#hashFunc(key);
+        this.#bucket[index] = new Entry(key, val);
+    }
+
+    /* 删除操作 */
+    delete(key) {
+        let index = this.#hashFunc(key);
+        // 置为 null ，代表删除
+        this.#bucket[index] = null;
+    }
+
+    /* 获取所有键值对 */
+    entries() {
+        let arr = [];
+        for (let i = 0; i < this.#bucket.length; i++) {
+            if (this.#bucket[i]) {
+                arr.push(this.#bucket[i]);
+            }
+        }
+        return arr;
+    }
+
+    /* 获取所有键 */
+    keys() {
+        let arr = [];
+        for (let i = 0; i < this.#bucket.length; i++) {
+            if (this.#bucket[i]) {
+                arr.push(this.#bucket[i]?.key);
+            }
+        }
+        return arr;
+    }
+
+    /* 获取所有值 */
+    values() {
+        let arr = [];
+        for (let i = 0; i < this.#bucket.length; i++) {
+            if (this.#bucket[i]) {
+                arr.push(this.#bucket[i]?.val);
+            }
+        }
+        return arr;
+    }
+
+    /* 打印哈希表 */
+    print() {
+        let entrySet = this.entries();
+        for (const entry of entrySet) {
+            if (!entry) continue;
+            console.info(`${entry.key} -> ${entry.val}`);
+        }
+    }
+}
+
+/* Driver Code */
+/* 初始化哈希表 */
+const map = new ArrayHashMap();
+/* 添加操作 */
+// 在哈希表中添加键值对 (key, value)
+map.set(12836, '小哈');
+map.set(15937, '小啰');
+map.set(16750, '小算');
+map.set(13276, '小法');
+map.set(10583, '小鸭');
+console.info('\n添加完成后，哈希表为\nKey -> Value');
+map.print();
+
+/* 查询操作 */
+// 向哈希表输入键 key ，得到值 value
+let name = map.get(15937);
+console.info('\n输入学号 15937 ，查询到姓名 ' + name);
+
+/* 删除操作 */
+// 在哈希表中删除键值对 (key, value)
+map.delete(10583);
+console.info('\n删除 10583 后，哈希表为\nKey -> Value');
+map.print();
+
+/* 遍历哈希表 */
+console.info('\n遍历键值对 Key->Value');
+for (const entry of map.entries()) {
+    if (!entry) continue;
+    console.info(entry.key + ' -> ' + entry.val);
+}
+console.info('\n单独遍历键 Key');
+for (const key of map.keys()) {
+    console.info(key);
+}
+console.info('\n单独遍历值 Value');
+for (const val of map.values()) {
+    console.info(val);
+}
diff --git a/codes/javascript/chapter_hashing/hash_map.js b/codes/javascript/chapter_hashing/hash_map.js
new file mode 100644
index 000000000..197fb7dd9
--- /dev/null
+++ b/codes/javascript/chapter_hashing/hash_map.js
@@ -0,0 +1,44 @@
+/*
+ * File: hash_map.js
+ * Created Time: 2022-12-26
+ * Author: Justin (xiefahit@gmail.com)
+ */
+
+/* Driver Code */
+/* 初始化哈希表 */
+const map = new Map();
+
+/* 添加操作 */
+// 在哈希表中添加键值对 (key, value)
+map.set(12836, '小哈');
+map.set(15937, '小啰');
+map.set(16750, '小算');
+map.set(13276, '小法');
+map.set(10583, '小鸭');
+console.info('\n添加完成后，哈希表为\nKey -> Value');
+console.info(map);
+
+/* 查询操作 */
+// 向哈希表输入键 key ，得到值 value
+let name = map.get(15937);
+console.info('\n输入学号 15937 ，查询到姓名 ' + name);
+
+/* 删除操作 */
+// 在哈希表中删除键值对 (key, value)
+map.delete(10583);
+console.info('\n删除 10583 后，哈希表为\nKey -> Value');
+console.info(map);
+
+/* 遍历哈希表 */
+console.info('\n遍历键值对 Key->Value');
+for (const [k, v] of map.entries()) {
+    console.info(k + ' -> ' + v);
+}
+console.info('\n单独遍历键 Key');
+for (const k of map.keys()) {
+    console.info(k);
+}
+console.info('\n单独遍历值 Value');
+for (const v of map.values()) {
+    console.info(v);
+}