add contains and removeAt functions

Author: amejiarosario

.vscode/launch.json

@@ -7,8 +7,20 @@
     {
       "type": "node",
       "request": "launch",
-      "name": "HashMap",
-      "program": "${workspaceFolder}/src/runtimes/linear/hash-map.js"
+      "name": "Jest All",
+      "program": "${workspaceFolder}/node_modules/jest/bin/jest",
+      "args": ["--runInBand"],
+      "console": "integratedTerminal",
+      "internalConsoleOptions": "neverOpen"
+    },
+    {
+      "type": "node",
+      "request": "launch",
+      "name": "Jest Current File",
+      "program": "${workspaceFolder}/node_modules/jest/bin/jest",
+      "args": ["${relativeFile}"],
+      "console": "integratedTerminal",
+      "internalConsoleOptions": "neverOpen"
     }
   ]
 }

lib/data-structures/linked-lists/linked-list-1.js

@@ -75,6 +75,34 @@ class LinkedList {
       return target.value;
     }
   }
+
+  /**
+   * Find first occurence of the element matching the value
+   * return index or undefined
+   * Runtime: O(n)
+   * @param {any} value
+   */
+  contains(value) {
+    for (let current = this.first, index = 0; current;  index++, current = current.next) {
+      if(current.value === value) {
+        return index;
+      }
+    }
+  }
+
+  /**
+   * Remove the nth element from the list. Starting with 0
+   * Returns value if found or undefined if it was not found
+   * Runtime: O(n)
+   * @param {any} nth
+   */
+  removeAt(nth) {
+    for (let current = this.first, index = 0; current;  index++, current = current.next) {
+      if(index === nth) {
+        return current.value;
+      }
+    }
+  }
 }
 
 module.exports = LinkedList;

lib/data-structures/linked-lists/linked-list-2.js

@@ -83,6 +83,34 @@ class LinkedList {
       return target.value;
     }
   }
+
+    /**
+   * Find first occurence of the element matching the value
+   * return index or undefined
+   * Runtime: O(n)
+   * @param {any} value
+   */
+  contains(value) {
+    for (let current = this.first, index = 0; current;  index++, current = current.next) {
+      if(current.value === value) {
+        return index;
+      }
+    }
+  }
+
+  /**
+   * Remove the nth element from the list. Starting with 0
+   * Returns value if found or undefined if it was not found
+   * Runtime: O(n)
+   * @param {any} nth
+   */
+  removeAt(nth) {
+    for (let current = this.first, index = 0; current;  index++, current = current.next) {
+      if(index === nth) {
+        return current.value;
+      }
+    }
+  }
 }
 
 // Aliases

lib/data-structures/linked-lists/linked-list.js

@@ -103,6 +103,34 @@ class LinkedList {
       return target.value;
     }
   }
+
+  /**
+   * Find first occurence of the element matching the value
+   * return index or undefined
+   * Runtime: O(n)
+   * @param {any} value
+   */
+  contains(value) {
+    for (let current = this.first, index = 0; current;  index++, current = current.next) {
+      if(current.value === value) {
+        return index;
+      }
+    }
+  }
+
+  /**
+   * Remove the nth element from the list. Starting with 0
+   * Returns value if found or undefined if it was not found
+   * Runtime: O(n)
+   * @param {any} nth
+   */
+  removeAt(nth) {
+    for (let current = this.first, index = 0; current;  index++, current = current.next) {
+      if(index === nth) {
+        return current.value;
+      }
+    }
+  }
 }
 
 // Aliases

lib/data-structures/linked-lists/linked-list.spec.js

@@ -90,6 +90,36 @@ describe('LinkedList', function () {
     });
   });
 
+  describe('with elements', () => {
+    beforeEach(() => {
+      linkedList.addLast(0);
+      linkedList.addLast('found');
+    });
+
+    describe('#contains', () => {
+      it('should find elements', () => {
+        expect(linkedList.contains(0)).toBe(0);
+        expect(linkedList.contains('found')).toBe(1);
+      });
+
+      it('should return undefined', () => {
+        expect(linkedList.contains('hola')).toBe(undefined);
+      });
+    });
+
+    describe('#removeAt', () => {
+      it('should remove element and return value', () => {
+        expect(linkedList.removeAt(1)).toBe('found');
+        expect(linkedList.removeAt(0)).toBe(0);
+      });
+
+      it('should return undefined ', () => {
+        expect(linkedList.removeAt(2)).toBe(undefined);
+        expect(linkedList.removeAt(-2)).toBe(undefined);
+      });
+    });
+  });
+
   describe('Doubly Linked List and aliases', () => {
 
     describe('#addLast', () => {