update: graph implementation, filter in LL, eslit & prettier fix

Author: ashokdey

.eslintrc.json

@@ -3,6 +3,9 @@
     "node": true,
     "jest": true
   },
-  "extends": ["prettier", "airbnb-base"],
-  "plugins": ["prettier"]
+  "extends": ["airbnb", "plugin:prettier/recommended", "plugin:node/recommended"],
+  "plugins": ["prettier"],
+  "rules": {
+    "prettier/prettier": "error"
+  }
 }

.prettierrc.js

@@ -1,7 +1,8 @@
 module.exports = {
   semi: true,
-  trailingComma: "all",
+  trailingComma: 'all',
   singleQuote: true,
   printWidth: 120,
-  tabWidth: 2
+  tabWidth: 2,
+  arrowParens: 'always',
 };

package-lock.json

@@ -16,10 +16,13 @@
   "author": "Ashok Dey <ashokdey100@gmail.com> (http://ashokdey.in)",
   "license": "MIT",
   "devDependencies": {
-    "eslint": "^5.11.1",
+    "eslint": "^5.16.0",
+    "eslint-config-airbnb": "^18.0.1",
     "eslint-config-airbnb-base": "^13.1.0",
-    "eslint-config-prettier": "^6.5.0",
+    "eslint-config-node": "^4.0.0",
+    "eslint-config-prettier": "^6.7.0",
     "eslint-plugin-import": "^2.14.0",
+    "eslint-plugin-node": "^10.0.0",
     "eslint-plugin-prettier": "^3.1.1",
     "jest": "^25.0.0",
     "prettier": "^1.19.1"

package.json

@@ -0,0 +1,103 @@
+const { LinkedList } = require('../LinkedList');
+
+class Graph {
+  constructor() {
+    this.data = this.getStorage();
+  }
+
+  addVertex(v) {
+    this.data.addVertex(v);
+  }
+
+  addEdge(v, e) {
+    this.data.addEdge(v, e);
+  }
+
+  removeEdge(v, e) {
+    this.data.removeEdge(v, e);
+  }
+
+  removeVertex(v) {
+    this.data.removeVertex(v);
+  }
+
+  getEdges(v) {
+    return this.data.getEdges(v);
+  }
+
+  displayMatrix() {
+    return this.data.displayMatrix();
+  }
+
+  // eslint-disable-next-line class-methods-use-this
+  getStorage() {
+    const map = {};
+
+    return {
+      addVertex(v) {
+        if (!map[v]) map[v] = new LinkedList();
+      },
+      addEdge(v, e) {
+        if (map[v]) {
+          map[v].addAtEnd(e);
+        }
+      },
+      removeEdge(v, e) {
+        if (map[v]) {
+          map[v].filter(e);
+        }
+      },
+      removeVertex(v) {
+        if (map[v]) {
+          delete map[v];
+
+          const vertices = Object.keys(map);
+          const edge = v; // this vertex may be an edge for other vertices
+          vertices.forEach((vertex) => this.removeEdge(vertex, edge));
+        }
+      },
+      getEdges(v) {
+        if (map[v]) {
+          return map[v].traverseList();
+        }
+      },
+      displayMatrix() {
+        const vertices = Object.keys(map);
+        const result = {};
+
+        vertices.forEach((v) => {
+          result[v] = map[v].traverseList();
+        });
+        return result;
+      },
+    };
+  }
+}
+
+// const g = new Graph();
+
+// g.addVertex('Noida');
+// console.log(g.displayMatrix());
+
+// g.addEdge('Noida', 'Greater Noida');
+// g.addEdge('Noida', 'Ghaziabaad');
+// g.addEdge('Noida', 'Meerut');
+// g.addEdge('Noida', 'Greater Noida');
+// g.addEdge('Noida', 'Mathura');
+
+// g.addVertex('Mathura');
+// g.addEdge('Mathura', 'Noida');
+// g.addEdge('Mathura', 'Meerut');
+// console.log(g.displayMatrix());
+// // g.data['Noida'].size = 10;
+
+// // console.log(g.data['Noida']);
+// // g.filter('Noida', 'Greater Noida');
+// console.log(g.displayMatrix());
+// console.log('removing Mathura');
+
+// g.removeVertex('Mathura');
+// console.log(g.displayMatrix());
+// console.log(g.getEdges('Noida'));
+
+module.exports = Graph;

src/_DataStructures_/Graphs/index.js

@@ -168,11 +168,14 @@ class LinkedList {
       if (head.data === value) {
         previous.next = head.next;
         this.size -= 1;
+
+        if (head.next === null) {
+          this.tail = previous;
+        }
       }
       previous = head;
       head = head.next;
     }
-
     return this.head;
   }
 
@@ -211,4 +214,14 @@ class LinkedList {
 // console.log(ll.removeAt(1));
 // console.log(ll.traverseList());
 
+// const list = new LinkedList();
+// [1, 2, 3, 5, 3, 6, 7, 10, 3].forEach(el => {
+//   list.addAtEnd(el);
+// });
+
+// console.log(list.traverseList());
+// list.filter(3);
+// console.log(list.traverseList());
+// console.log(list.tail);
+
 module.exports = { LinkedList, Node };