From e87e38b62b4f734bf42a5be48f06ca213a8ac49f Mon Sep 17 00:00:00 2001
From: oleksii golikov <og@vi.ai>
Date: Mon, 9 Jul 2018 21:36:34 +0300
Subject: [PATCH] single and doubly lists

---
 JavaScript/7-single.js | 64 ++++++++++++++++++++++++++++++++++++++++
 JavaScript/8-doubly.js | 66 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 130 insertions(+)
 create mode 100644 JavaScript/7-single.js
 create mode 100644 JavaScript/8-doubly.js

diff --git a/JavaScript/7-single.js b/JavaScript/7-single.js
new file mode 100644
index 0000000..b01fef0
--- /dev/null
+++ b/JavaScript/7-single.js
@@ -0,0 +1,64 @@
+
+const Node = (value, next = null) => ({
+  value,
+  next,
+});
+
+const LinkedList = () => {
+  const list = {
+    head: null,
+    
+    append(value) {
+      if (!list.head) {
+        list.head = Node(value)
+      } else {
+        let node = list.head;
+        while (node.next) {
+          node = node.next;
+        }
+        node.next = Node(value);
+      }
+    },
+    
+    remove(value) {
+      let prev = null;
+      let node = list.head;
+      
+      while (node) {
+        if (node.value === value) {
+          if (node === list.head) {
+            list.head = node.next;
+          } else {
+            prev.next = node.next;
+          }
+        }
+        prev = node;
+        node = node.next;
+      }
+    },
+    
+    [Symbol.iterator]: function* () {
+      let node = list.head;
+      while (node) {
+        yield node.value;
+        node = node.next;
+      }
+    }
+  };
+  return list;
+};
+
+// Usage
+
+const list = LinkedList();
+
+list.append(1);
+list.append(2);
+list.append(3);
+list.append(4);
+list.remove(3);
+
+for (item of list) {
+  console.log(item);
+}
+
diff --git a/JavaScript/8-doubly.js b/JavaScript/8-doubly.js
new file mode 100644
index 0000000..b7db993
--- /dev/null
+++ b/JavaScript/8-doubly.js
@@ -0,0 +1,66 @@
+
+const Node = (value, prev = null, next = null) => ({
+  value,
+  prev,
+  next,
+});
+
+const DoublyLinkedList = () => {
+  const list = {
+    head: null,
+    
+    append(value) {
+      if (!list.head) {
+        list.head = Node(value)
+      } else {
+        let node = list.head;
+        while (node.next) {
+          node = node.next;
+        }
+        node.next = Node(value, node);
+      }
+    },
+    
+    remove(value) {
+      let node = list.head;
+      
+      while (node) {
+        if (node.value === value) {
+          if (node === list.head) {
+            list.head = node.next;
+          } else {
+            node.prev.next = node.next;
+            if (node.next) {
+              node.next.prev = node.prev;
+            }
+          }
+        }
+        node = node.next;
+      }
+    },
+    
+    [Symbol.iterator]: function* () {
+      let node = list.head;
+      while (node) {
+        yield node.value;
+        node = node.next;
+      }
+    }
+  };
+  return list;
+};
+
+// Usage
+
+const list = DoublyLinkedList();
+
+list.append(1);
+list.append(2);
+list.append(3);
+list.append(4);
+list.remove(3);
+
+for (item of list) {
+  console.log(item);
+}
+