Data Structures: Search within a Linked List

Data Structures/linkedListClassSearch.js

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+// https://www.freecodecamp.org/learn/coding-interview-prep/data-structures/search-within-a-linked-list
+
+function LinkedList() {
+  var length = 0;
+  var head = null;
+
+  var Node = function (element) {
+    this.element = element;
+    this.next = null;
+  };
+
+  this.size = function () {
+    return length;
+  };
+
+  this.head = function () {
+    return head;
+  };
+
+  this.add = function (element) {
+    var node = new Node(element);
+    if (head === null) {
+      head = node;
+    } else {
+      var currentNode = head;
+
+      while (currentNode.next) {
+        currentNode = currentNode.next;
+      }
+
+      currentNode.next = node;
+    }
+
+    length++;
+  };
+
+  this.remove = function (element) {
+    var currentNode = head;
+    var previousNode;
+    if (currentNode.element === element) {
+      head = currentNode.next;
+    } else {
+      while (currentNode.element !== element) {
+        previousNode = currentNode;
+        currentNode = currentNode.next;
+      }
+
+      previousNode.next = currentNode.next;
+    }
+
+    length--;
+  };
+
+  // Only change code below this line
+  this.isEmpty = () => {
+    return head === null;
+  };
+
+  this.indexOf = (element) => {
+    let i = 0;
+    let node = head;
+    while (node !== null && node.element !== element) {
+      i++;
+      node = node.next;
+    }
+    if (node === null) return -1;
+    return i;
+  };
+
+  this.elementAt = (index) => {
+    if (index < 0 || index >= length || head === null) {
+      return undefined;
+    }
+    let i = 0;
+    let node = head;
+    while (i < index && node !== null) {
+      i++;
+      node = node.next;
+    }
+    if (i != index) {
+      return undefined;
+    }
+    return node.element;
+  };
+  // Only change code above this line
+}