In this answer, I will provide you with a simple REST API using Node.js and Express.js for a Todo List application, as well as another API for basic arithmetic operations. For the purpose of this example, I'll use an in-memory array to store the todo items. In a real-world application, you would use a database.

First, create a new directory for your project and initialize it with npm:

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mkdir todo-api
cd todo-api
npm init -y

Install the required dependencies:

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npm install express body-parser

Create a new file named app.js and add the following code:

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const express = require("express");
const bodyParser = require("body-parser");

const app = express();
app.use(bodyParser.json());

// In-memory storage for Todo items
const todos = [];

// Todo List API
app.get("/todos", (req, res) => {
  res.json(todos);
});

app.post("/todos", (req, res) => {
  const newTodo = {
    id: todos.length + 1,
    title: req.body.title,
    completed: false,
  };
  todos.push(newTodo);
  res.json(newTodo);
});

app.put("/todos/:id", (req, res) => {
  const todo = todos.find((t) => t.id === parseInt(req.params.id));
  if (!todo) return res.status(404).send("Todo not found");

  todo.title = req.body.title || todo.title;
  todo.completed = req.body.completed ?? todo.completed;

  res.json(todo);
});

app.delete("/todos/:id", (req, res) => {
  const index = todos.findIndex((t) => t.id === parseInt(req.params.id));
  if (index === -1) return res.status(404).send("Todo not found");

  todos.splice(index, 1);
  res.status(204).send();
});

// Basic Arithmetic API
app.post("/calculate", (req, res) => {
  const { operation, a, b } = req.body;
  let result;

  switch (operation) {
    case "add":
      result = a + b;
      break;
    case "subtract":
      result = a - b;
      break;
    case "multiply":
      result = a * b;
      break;
    case "divide":
      if (b === 0) {
        return res.status(400).send("Division by zero is not allowed");
      }
      result = a / b;
      break;
    default:
      return res.status(400).send("Invalid operation");
  }

  res.json({ result });
});

// Start server
const port = process.env.PORT || 3000;
app.listen(port, () => {
  console.log(`Server started on port ${port}`);
});

This API provides endpoints for creating, reading, updating, and deleting todo items, as well as an endpoint for basic arithmetic operations.

To test your API, you can use tools like Postman or Insomnia, or even use the command line with tools like curl.

Below is the OpenAPI 3.0 document for the Todo List and Arithmetic API. Save this JSON in a file called openapi.json in your project directory:

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{
  "openapi": "3.0.0",
  "info": {
    "title": "Todo List and Arithmetic API",
    "version": "1.0.0"
  },
  "servers": [
    {
      "url": "http://localhost:3000"
    }
  ],
  "paths": {
    "/todos": {
      "get": {
        "summary": "Get all todos",
        "responses": {
          "200": {
            "description": "List of todos",
            "content": {
              "application/json": {
                "schema": {
                  "type": "array",
                  "items": {
                    "$ref": "#/components/schemas/Todo"
                  }
                }
              }
            }
          }
        }
      },
      "post": {
        "summary": "Create a new todo",
        "requestBody": {
          "content": {
            "application/json": {
              "schema": {
                "$ref": "#/components/schemas/NewTodo"
              }
            }
          },
          "required": true
        },
        "responses": {
          "200": {
            "description": "New todo created",
            "content": {
              "application/json": {
                "schema": {
                  "$ref": "#/components/schemas/Todo"
                }
              }
            }
          }
        }
      }
    },
    "/todos/{id}": {
      "put": {
        "summary": "Update a todo",
        "parameters": [
          {
            "name": "id",
            "in": "path",
            "required": true,
            "schema": {
              "type": "integer"
            }
          }
        ],
        "requestBody": {
          "content": {
            "application/json": {
              "schema": {
                "$ref": "#/components/schemas/UpdateTodo"
              }
            }
          },
          "required": true
        },
        "responses": {
          "200": {
            "description": "Todo updated",
            "content": {
              "application/json": {
                "schema": {
                  "$ref": "#/components/schemas/Todo"
                }
              }
            }
          },
          "404": {
            "description": "Todo not found"
          }
        }
      },
      "delete": {
        "summary": "Delete a todo",
        "parameters": [
          {
            "name": "id",
            "in": "path",
            "required": true,
            "schema": {
              "type": "integer"
            }
          }
        ],
        "responses": {
          "204": {
            "description": "Todo deleted"
          },
          "404": {
            "description": "Todo not found"
          }
        }
      }
    },
    "/calculate": {
      "post": {
        "summary": "Perform basic arithmetic operations",
        "requestBody": {
          "content": {
            "application/json": {
              "schema": {
                "$ref": "#/components/schemas/ArithmeticOperation"
              }
            }
          },
          "required": true
        },
        "responses": {
          "200": {
            "description": "Calculation result",
            "content": {
              "application/json": {
                "schema": {
                  "type": "object",
                  "properties": {
                    "result": {
                      "type": "number"
                    }
                  }
                }
              }
            }
          },
          "400": {
            "description": "Invalid

Here is the continuation of the OpenAPI 3.0 document:

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          "400": {
            "description": "Invalid operation or division by zero"
          }
        }
      }
    }
  },
  "components": {
    "schemas": {
      "Todo": {
        "type": "object",
        "properties": {
          "id": {
            "type": "integer"
          },
          "title": {
            "type": "string"
          },
          "completed": {
            "type": "boolean"
          }
        }
      },
      "NewTodo": {
        "type": "object",
        "properties": {
          "title": {
            "type": "string"
          }
        },
        "required": [
          "title"
        ]
      },
      "UpdateTodo": {
        "type": "object",
        "properties": {
          "title": {
            "type": "string"
          },
          "completed": {
            "type": "boolean"
          }
        }
      },
      "ArithmeticOperation": {
        "type": "object",
        "properties": {
          "operation": {
            "type": "string",
            "enum": [
              "add",
              "subtract",
              "multiply",
              "divide"
            ]
          },
          "a": {
            "type": "number"
          },
          "b": {
            "type": "number"
          }
        },
        "required": [
          "operation",
          "a",
          "b"
        ]
      }
    }
  }
}

Now, to view the API documentation using Swagger UI, you can follow these steps:

1. Install the swagger-ui-express package:

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npm install swagger-ui-express

1. Update app.js to include the Swagger UI middleware:

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const express = require("express");
const bodyParser = require("body-parser");
const swaggerUi = require("swagger-ui-express");
const openapiDocument = require("./openapi.json");

// ... (rest of the code)

// Add Swagger UI middleware
app.use("/api-docs", swaggerUi.serve, swaggerUi.setup(openapiDocument));

// ... (rest of the code)

1. Start your server:

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node app.js

1. Open your browser and navigate to http://localhost:3000/api-docs to view the Swagger UI documentation for your API.

Now you can explore the API documentation and even interact with the endpoints using the Swagger UI interface.

To create a test harness for the API, we can use Mocha, Chai, and Supertest. First, install the required dependencies:

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npm install mocha chai supertest --save-dev

Next, create a new directory called test in your project folder and add a file named api.test.js:

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mkdir test
touch test/api.test.js

Add the following test cases to test/api.test.js:

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const app = require("../app");
const request = require("supertest");
const { expect } = require("chai");

describe("Todo List and Arithmetic API", () => {
  describe("Todo List API", () => {
    let todoId;

    it("should create a new todo", async () => {
      const res = await request(app)
        .post("/todos")
        .send({ title: "Test Todo" });

      expect(res.status).to.equal(200);
      expect(res.body).to.have.property("id");
      expect(res.body).to.have.property("title", "Test Todo");
      expect(res.body).to.have.property("completed", false);

      todoId = res.body.id;
    });

    it("should get all todos", async () => {
      const res = await request(app).get("/todos");

      expect(res.status).to.equal(200);
      expect(res.body).to.be.an("array");
      expect(res.body).to.have.length(1);
    });

    it("should update a todo", async () => {
      const res = await request(app)
        .put(`/todos/${todoId}`)
        .send({ title: "Updated Todo", completed: true });

      expect(res.status).to.equal(200);
      expect(res.body).to.have.property("id", todoId);
      expect(res.body).to.have.property("title", "Updated Todo");
      expect(res.body).to.have.property("completed", true);
    });

    it("should delete a todo", async () => {
      const res = await request(app).delete(`/todos/${todoId}`);

      expect(res.status).to.equal(204);
    });
  });

  describe("Arithmetic API", () => {
    it("should add two numbers", async () => {
      const res = await request(app)
        .post("/calculate")
        .send({ operation: "add", a: 5, b: 3 });

      expect(res.status).to.equal(200);
      expect(res.body).to.have.property("result", 8);
    });

    it("should subtract two numbers", async () => {
      const res = await request(app)
        .post("/calculate")
        .send({ operation: "subtract", a: 5, b: 3 });

      expect(res.status).to.equal(200);
      expect(res.body).to.have.property("result", 2);
    });

    it("should multiply two numbers", async () => {
      const res = await request(app)
        .post("/calculate")
        .send({ operation: "multiply", a: 5, b: 3 });

      expect(res.status).to.equal(200);
      expect(res.body).to.have.property("result", 15);
    });

    it("should divide two numbers", async () => {
      const res = await request(app)
        .post("/calculate")
        .send({ operation: "divide", a: 6, b: 3 });

      expect(res.status).to.equal(200);
      expect(res.body).to.have.property("result", 2);
    });

    it("should return an error for division by zero", async () => {
      const res = await request(app)
        .post("/calculate")

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        .post("/calculate")
        .send({ operation: "divide", a: 6, b: 0 });

      expect(res.status).to.equal(400);
      expect(res.text).to.equal("Division by zero is not allowed");
    });

    it("should return an error for invalid operations", async () => {
      const res = await request(app)
        .post("/calculate")
        .send({ operation: "invalid", a: 6, b: 3 });

      expect(res.status).to.equal(400);
      expect(res.text).to.equal("Invalid operation");
    });
  });
});

Now, update your package.json file to include a test script:

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{
  "scripts": {
    "test": "mocha --exit"
  }
}

You can now run the test harness using the following command:

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npm test

This command will execute the test cases using Mocha. The test cases cover the main functionality of the Todo List and Arithmetic API. You should see the test results indicating if the tests have passed or failed.

Below is the list of files and the folder structure for the project we've built so far:

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todo-api/
|-- node_modules/
|   |-- (various dependencies and their files)
|-- test/
|   |-- api.test.js
|-- app.js
|-- openapi.json
|-- package-lock.json
|-- package.json

Here is a brief explanation of the files and folders:

1. node_modules/: This folder contains all the dependencies installed for the project.
2. test/: This folder contains the test files for the project.
   • api.test.js: This file contains the test cases for the Todo List and Arithmetic API.
3. app.js: This is the main entry point for the application, containing the server and API implementation.
4. openapi.json: This file contains the OpenAPI 3.0 specification for the Todo List and Arithmetic API.
5. package-lock.json: This file is automatically generated by npm and contains the exact dependency tree to ensure consistency across installations.
6. package.json: This file contains the project metadata, dependencies, and scripts.

Keep in mind that the node_modules folder will not be present until you run npm install, and it should not be committed to a version control system, like Git. You can add a .gitignore file to your project to prevent it from being committed.

To create a Vue.js application using Vue and Vuetify, follow these steps:

1. Install Vue CLI globally on your system, if you haven't already:

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npm install -g @vue/cli

1. Create a new Vue project:

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vue create todo-frontend

Select the default preset or customize it as per your preference.

1. Change to the new project directory:

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cd todo-frontend

1. Add Vuetify to the project:

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vue add vuetify

Select the preset you prefer (either default or custom).

1. Open the src/App.vue file and replace its content with the following:

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<template>
  <v-app>
    <SplashScreen v-if="showSplash" />
    <v-main v-else>
      <TodoList />
    </v-main>
  </v-app>
</template>

<script>
import SplashScreen from "./components/SplashScreen.vue";
import TodoList from "./components/TodoList.vue";

export default {
  name: "App",
  components: {
    SplashScreen,
    TodoList,
  },
  data() {
    return {
      showSplash: true,
    };
  },
  mounted() {
    setTimeout(() => {
      this.showSplash = false;
    }, 5000);
  },
};
</script>

1. Create a new file src/components/SplashScreen.vue and add the following content:

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<template>
  <v-container class="fill-height" fluid>
    <v-row align="center" justify="center">
      <v-col class="text-center">
        <h1>Welcome to the Todo App</h1>
        <p>Loading...</p>
      </v-col>
    </v-row>
  </v-container>
</template>

<script>
export default {
  name: "SplashScreen",
};
</script>

1. Create a new file src/components/TodoList.vue and add the following content:

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<template>
  <v-container>
    <v-row>
      <v-col>
        <h1>Todo List</h1>
        <v-text-field
          v-model="newTodoTitle"
          label="New Todo"
          @keyup.enter="addTodo"
        ></v-text-field>
        <v-list>
          <v-list-item v-for="(todo, index) in todos" :key="todo.id">
            <v-list-item-content>
              <v-checkbox
                v-model="todo.completed"
                :label="todo.title"
                @change="updateTodo(todo)"
              ></v-checkbox>
            </v-list-item-content>
            <v-list-item-action>
              <v-btn icon @click="editTodo(index)">
                <v-icon>mdi-pencil</v-icon>
              </v-btn>
              <v-btn icon @click="deleteTodo(todo.id)">
                <v-icon>mdi-delete</v-icon>
              </v-btn>
            </v-list-item-action>
          </v-list-item>
        </v-list>
      </v-col>
    </v-row>
  </v-container>
</template>

<script>
import axios from "axios";

export default {
  name: "TodoList",
  data() {
    return {
      todos: [],
      newTodoTitle: "",
    };
  },
  async mounted() {
    this.todos = await this.fetchTodos();
  },
  methods: {
    async fetchTodos() {
      const response = await axios.get("http://localhost:3000/todos");
      return response.data;
    },
    async addTodo() {
      if (this.newTodoTitle.trim()) {
        const response =

Here's the continuation of the src/components/TodoList.vue file:

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        const response = await axios.post("http://localhost:3000/todos", {
          title: this.newTodoTitle.trim(),
        });
        this.todos.push(response.data);
        this.newTodoTitle = "";
      }
    },
    async updateTodo(todo) {
      await axios.put(`http://localhost:3000/todos/${todo.id}`, {
        title: todo.title,
        completed: todo.completed,
      });
    },
    async deleteTodo(id) {
      await axios.delete(`http://localhost:3000/todos/${id}`);
      this.todos = this.todos.filter((todo) => todo.id !== id);
    },
    editTodo(index) {
      this.newTodoTitle = this.todos[index].title;
      this.deleteTodo(this.todos[index].id);
    },
  },
};
</script>

1. In the src/main.js file, add the following line to import Axios:

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import axios from "axios";

Then, add the following line below the import statements to make Axios available globally in your Vue app:

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Vue.prototype.$axios = axios;

Now, you have a Vue.js application with Vuetify that communicates with the Todo List API. The application has a splash screen that appears for 5 seconds before taking the user to the main application window, where they can add, edit, update, and remove todo list items.

To run the application, use the following command:

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npm run serve

The application will be available at http://localhost:8080. Note that you need to run the Node.js API server (on port 3000) for the frontend application to work correctly.

To integrate SQLite into your Node.js backend, we will use the sqlite3 package. First, install it:

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npm install sqlite3

Now, create a new file called db.js in your project folder:

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touch db.js

Add the following code to db.js to set up the SQLite database:

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const sqlite3 = require("sqlite3").verbose();
const db = new sqlite3.Database(":memory:");

db.serialize(() => {
  db.run(
    `CREATE TABLE todos (
        id INTEGER PRIMARY KEY AUTOINCREMENT,
        title TEXT NOT NULL,
        completed BOOLEAN DEFAULT 0
    )`
  );
});

module.exports = db;

Now, update the app.js file to use the SQLite database instead of the in-memory storage:

1. Replace the const todos = []; line with the following import statement:

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const db = require("./db");

1. Update the GET /todos route handler:

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app.get("/todos", (req, res) => {
  db.all("SELECT * FROM todos", (err, rows) => {
    if (err) {
      return res.status(500).send("Error retrieving todos");
    }
    res.json(rows);
  });
});

1. Update the POST /todos route handler:

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app.post("/todos", (req, res) => {
  const { title } = req.body;

  db.run("INSERT INTO todos (title) VALUES (?)", [title], function (err) {
    if (err) {
      return res.status(500).send("Error adding todo");
    }
    res.status(200).json({ id: this.lastID, title, completed: false });
  });
});

1. Update the PUT /todos/:id route handler:

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app.put("/todos/:id", (req, res) => {
  const { id } = req.params;
  const { title, completed } = req.body;

  db.run(
    "UPDATE todos SET title = ?, completed = ? WHERE id = ?",
    [title, completed, id],
    function (err) {
      if (err) {
        return res.status(500).send("Error updating todo");
      }
      if (this.changes === 0) {
        return res.status(404).send("Todo not found");
      }
      res.json({ id, title, completed });
    }
  );
});

1. Update the DELETE /todos/:id route handler:

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app.delete("/todos/:id", (req, res) => {
  const { id } = req.params;

  db.run("DELETE FROM todos WHERE id = ?", [id], function (err) {
    if (err) {
      return res.status(500).send("Error deleting todo");
    }
    if (this.changes === 0) {
      return res.status(404).send("Todo not found");
    }
    res.sendStatus(204);
  });
});

Now, your Node.js API uses SQLite as a storage solution for the todo list items. Since we're using an in-memory SQLite database, the data will be lost when the server restarts. To persist the data, replace :memory: in db.js with the path to a file on your filesystem, for example, ./todos.db.

To add a login screen to the application and support Google and Facebook login, you will need to implement authentication and user management in the backend. We'll use Passport.js, a popular authentication library for Node.js, and its Google and Facebook strategies.

First, install the necessary packages:

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npm install passport passport-google-oauth20 passport-facebook express-session

Create a new file config.js to store the Google and Facebook credentials:

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module.exports = {
  google: {
    clientID: "YOUR_GOOGLE_CLIENT_ID",
    clientSecret: "YOUR_GOOGLE_CLIENT_SECRET",
  },
  facebook: {
    clientID: "YOUR_FACEBOOK_APP_ID",
    clientSecret: "YOUR_FACEBOOK_APP_SECRET",
  },
  session: {
    cookieKey: "somesecretkey",
  },
};

Replace YOUR_GOOGLE_CLIENT_ID, YOUR_GOOGLE_CLIENT_SECRET, YOUR_FACEBOOK_APP_ID, and YOUR_FACEBOOK_APP_SECRET with the appropriate credentials from the Google and Facebook developer consoles.

Update db.js to add a users table:

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db.serialize(() => {
  db.run(
    `CREATE TABLE users (
        id INTEGER PRIMARY KEY AUTOINCREMENT,
        googleId TEXT,
        facebookId TEXT,
        displayName TEXT
    )`
  );
  db.run(
    `CREATE TABLE todos (
        id INTEGER PRIMARY KEY AUTOINCREMENT,
        title TEXT NOT NULL,
        completed BOOLEAN DEFAULT 0,
        userId INTEGER,
        FOREIGN KEY (userId) REFERENCES users (id)
    )`
  );
});

Update app.js to set up Passport, Google and Facebook strategies, and session handling:

1. Import the required modules at the top of the file:

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const session = require("express-session");
const passport = require("passport");
const GoogleStrategy = require("passport-google-oauth20").Strategy;
const FacebookStrategy = require("passport-facebook").Strategy;
const config = require("./config");

1. Set up session handling after initializing the app variable:

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app.use(
  session({
    secret: config.session.cookieKey,
    resave: false,
    saveUninitialized: false,
  })
);
app.use(passport.initialize());
app.use(passport.session());

1. Add Passport.js Google and Facebook strategy configurations:

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passport.serializeUser((user, done) => {
  done(null, user.id);
});

passport.deserializeUser((id, done) => {
  db.get("SELECT * FROM users WHERE id = ?", [id], (err, row) => {
    done(err, row);
  });
});

passport.use(
  new GoogleStrategy(
    {
      clientID: config.google.clientID,
      clientSecret: config.google.clientSecret,
      callbackURL: "/auth/google/callback",
    },
    (accessToken, refreshToken, profile, done) => {
      db.get(
        "SELECT * FROM users WHERE googleId = ?",
        [profile.id],
        (err, row) => {
          if (row) {
            return done(null, row);
          } else {
            db.run(
              "INSERT INTO users (googleId, displayName) VALUES (?, ?)",
              [profile.id, profile.displayName],
              function (err) {
                if (err) {
                  return done(err);
                }
                db.get(
                  "SELECT * FROM users WHERE id = ?",
                  [this.lastID],
                  (err, row) => {
                    done(err, row);
                  }
                );
              }
            );
          }
        }
      );
    }
  )
);

passport.use(
  new FacebookStrategy(
    {
      clientID: config.facebook.clientID,
      clientSecret: config.facebook.clientSecret,

Here's the continuation of the Passport.js Facebook strategy configuration in app.js:

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      clientID: config.facebook.clientID,
      clientSecret: config.facebook.clientSecret,
      callbackURL: "/auth/facebook/callback",
      profileFields: ["id", "displayName"],
    },
    (accessToken, refreshToken, profile, done) => {
      db.get(
        "SELECT * FROM users WHERE facebookId = ?",
        [profile.id],
        (err, row) => {
          if (row) {
            return done(null, row);
          } else {
            db.run(
              "INSERT INTO users (facebookId, displayName) VALUES (?, ?)",
              [profile.id, profile.displayName],
              function (err) {
                if (err) {
                  return done(err);
                }
                db.get(
                  "SELECT * FROM users WHERE id = ?",
                  [this.lastID],
                  (err, row) => {
                    done(err, row);
                  }
                );
              }
            );
          }
        }
      );
    }
  )
);

1. Add the Google and Facebook authentication routes:

javascriptCopy code
app.get("/auth/google", passport.authenticate("google", { scope: ["profile"] }));

app.get(
  "/auth/google/callback",
  passport.authenticate("google"),
  (req, res) => {
    res.redirect("/"); // Redirect to the main application
  }
);

app.get("/auth/facebook", passport.authenticate("facebook"));

app.get(
  "/auth/facebook/callback",
  passport.authenticate("facebook"),
  (req, res) => {
    res.redirect("/"); // Redirect to the main application
  }
);

app.get("/logout", (req, res) => {
  req.logout();
  res.redirect("/");
});

1. Update the /todos routes to filter todos based on the authenticated user:

javascriptCopy code
app.get("/todos", (req, res) => {
  if (!req.user) {
    return res.status(401).send("Unauthorized");
  }

  db.all("SELECT * FROM todos WHERE userId = ?", [req.user.id], (err, rows) => {
    if (err) {
      return res.status(500).send("Error retrieving todos");
    }
    res.json(rows);
  });
});

app.post("/todos", (req, res) => {
  if (!req.user) {
    return res.status(401).send("Unauthorized");
  }

  const { title } = req.body;

  db.run(
    "INSERT INTO todos (title, userId) VALUES (?, ?)",
    [title, req.user.id],
    function (err) {
      if (err) {
        return res.status(500).send("Error adding todo");
      }
      res.status(200).json({ id: this.lastID, title, completed: false });
    }
  );
});

// Update the other /todos routes in a similar way

In your Vue.js frontend application, update the components to handle login and logout:

1. Create a new file src/components/Login.vue and add the following content:

htmlCopy code
<template>
  <v-container>
    <v-row>
      <v-col>
        <h1>Login</h1>
        <v-btn href="/auth/google" color="primary">Login with Google</v-btn>
        <v-btn href="/auth/facebook" color="primary">Login with Facebook</v-btn>
      </v-col>
    </v-row>
  </v-container>
</template>

<script>
export default {
  name: "Login",
};
</script>

1. Create a new file src/components/Logout.vue and add the following content:

htmlCopy code
<template>
  <v-btn @

Click="logout" color="primary">Logout</v-btn> </template>

phpCopy code

3. Update the `src/components/App.vue` file to display the login and logout buttons based on the authentication status:

```html
<template>
  <v-app>
    <v-main>
      <v-container>
        <v-row>
          <v-col>
            <router-link to="/">Home</router-link>
            <router-link v-if="!loggedIn" to="/login">Login</router-link>
            <Logout v-if="loggedIn" />
          </v-col>
        </v-row>
        <router-view />
      </v-container>
    </v-main>
  </v-app>
</template>

<script>
import Logout from "./Logout";

export default {
  name: "App",
  components: {
    Logout,
  },
  computed: {
    loggedIn() {
      return !!document.cookie.match(/connect.sid/);
    },
  },
};
</script>

1. Update the src/router/index.js file to add routes for the login component:

javascriptCopy code
import Login from "../components/Login.vue";

const routes = [
  // ...
  {
    path: "/login",
    name: "Login",
    component: Login,
  },
];

Now, the application has a login screen and supports Google and Facebook authentication. Users can log in using their Google or Facebook accounts, and each user will only see their own todos.

Here's the list of files and folders generated so far:

luaCopy code
backend/
│   app.js
│   config.js
│   db.js
│   package.json
│
frontend/
│   package.json
│
└───src/
    │   main.js
    │   App.vue
    │
    ├───components/
    │       TodoList.vue
    │       AddTodo.vue
    │       EditTodo.vue
    │       Splash.vue
    │       Login.vue
    │       Logout.vue
    │
    ├───router/
    │       index.js
    │
    └───store/
            index.js

backend/ contains the Node.js backend with Express, Passport.js for authentication, and SQLite for the database. frontend/ contains the Vue.js frontend application using Vuetify and Vue Router.

To implement this feature, you'll need to call the ChatGPT API as the user types, and then display the suggested completions. You can use the v-autocomplete component from Vuetify for this purpose. Make sure to handle API rate limits and avoid sending too many requests.

First, install axios to make API requests from the frontend:

bashCopy code
npm install axios

Next, update the frontend/src/components/AddTodo.vue file with the following changes:

1. Import axios and the ChatGPT API key:

javascriptCopy code
import axios from "axios";

const chatGptApiKey = "your_chatgpt_api_key";

Replace your_chatgpt_api_key with your actual API key.

1. Add a search method to fetch completions from the ChatGPT API:

javascriptCopy code
methods: {
  // ...
  async search(input, callback) {
    try {
      const response = await axios.post(
        "https://api.openai.com/v1/engines/davinci-codex/completions",
        {
          prompt: `Create a todo item: ${input}`,
          max_tokens: 10,
          n: 5,
          stop: null,
          temperature: 0.7,
        },
        {
          headers: {
            "Content-Type": "application/json",
            Authorization: `Bearer ${chatGptApiKey}`,
          },
        }
      );

      const completions = response.data.choices.map((choice) => {
        return input + choice.text.trim();
      });

      callback(completions);
    } catch (error) {
      console.error("Error fetching completions:", error);
      callback([]);
    }
  },
},

1. Replace the v-text-field component with a v-autocomplete component:

htmlCopy code
<v-autocomplete
  v-model="title"
  :loading="isLoading"
  :search-input.sync="searchText"
  :items="suggestions"
  label="Add a new todo"
  @input="addTodo"
></v-autocomplete>

1. Add data properties for isLoading, searchText, and suggestions:

javascriptCopy code
data() {
  return {
    title: "",
    isLoading: false,
    searchText: "",
    suggestions: [],
  };
},

1. Add a watcher for searchText to debounce the API calls:

javascriptCopy code
watch: {
  searchText(value) {
    if (value && value.length > 2) {
      this.isLoading = true;
      clearTimeout(this.searchDebounce);
      this.searchDebounce = setTimeout(() => {
        this.search(value, (items) => {
          this.suggestions = items;
          this.isLoading = false;
        });
      }, 500);
    } else {
      this.suggestions = [];
    }
  },
},

Now, as the user types a new todo item, the application will fetch text completions from the ChatGPT API and display them as selectable suggestions. Note that you may need to adjust the prompt, parameters, and the ChatGPT API URL according to your specific use case and API version.

To make the ChatGPT API call through the Node.js server, you'll need to create a new API route on the backend that handles this request and then update the frontend to call this new API route.

1. In the backend/app.js file, add a new route for ChatGPT API requests:

javascriptCopy code
const axios = require("axios");

const chatGptApiKey = "your_chatgpt_api_key";

app.post("/chatgpt", async (req, res) => {
  const { input } = req.body;

  try {
    const response = await axios.post(
      "https://api.openai.com/v1/engines/davinci-codex/completions",
      {
        prompt: `Create a todo item: ${input}`,
        max_tokens: 10,
        n: 5,
        stop: null,
        temperature: 0.7,
      },
      {
        headers: {
          "Content-Type": "application/json",
          Authorization: `Bearer ${chatGptApiKey}`,
        },
      }
    );

    const completions = response.data.choices.map((choice) => {
      return input + choice.text.trim();
    });

    res.json(completions);
  } catch (error) {
    console.error("Error fetching completions:", error);
    res.status(500).json({ error: "Error fetching completions" });
  }
});

1. Update the frontend/src/components/AddTodo.vue file to call the new backend route:

Replace the search method with the following:

javascriptCopy code
async search(input, callback) {
  try {
    const response = await axios.post("/chatgpt", { input });
    callback(response.data);
  } catch (error) {
    console.error("Error fetching completions:", error);
    callback([]);
  }
},

Now, the frontend will call the Node.js server to fetch completions from the ChatGPT API, and the server will handle the API requests. This approach helps to hide the API key from the client-side code and centralizes API calls to the backend.

To create a Docker image with both the backend and frontend, you can use a multi-stage build. This will allow you to build the frontend and backend separately, and then copy the built files into the final container image.

Create a Dockerfile in the root directory of your project with the following content:

DockerfileCopy code
# --- Build frontend ---
FROM node:16-alpine as frontend-builder
WORKDIR /app/frontend

COPY frontend/package.json frontend/package-lock.json ./
RUN npm ci

COPY frontend .
RUN npm run build

# --- Build backend ---
FROM node:16-alpine as backend-builder
WORKDIR /app/backend

COPY backend/package.json backend/package-lock.json ./
RUN npm ci

COPY backend .
RUN npm run build

# --- Final container image ---
FROM node:16-alpine
WORKDIR /app

COPY --from=backend-builder /app/backend /app/backend
COPY --from=frontend-builder /app/frontend/dist /app/frontend/dist

# Expose the API port
EXPOSE 3000

# Set the working directory for the backend
WORKDIR /app/backend

# Start the backend server
CMD ["npm", "start"]

This Dockerfile uses three stages:

1. frontend-builder: Builds the frontend using the Vue CLI. It installs the necessary dependencies, copies the frontend source code, and runs the build command. The built files will be placed in the dist folder.
2. backend-builder: Builds the backend using Node.js. It installs the necessary dependencies and copies the backend source code.
3. The final stage: Copies the built frontend files from the frontend-builder stage and the backend files from the backend-builder stage into a new container image based on the node:16-alpine image. It sets up the working directory and exposes the API port (3000).

To build the Docker image, run the following command in the same directory as the Dockerfile:

bashCopy code
docker build -t your-image-name .

Replace your-image-name with a name for your Docker image.

To run the Docker container, use the following command:

bashCopy code
docker run -p 3000:3000 your-image-name

This will start the container and map the API port 3000 to the host machine, allowing you to access the API at http://localhost:3000.

Here's the updated list of files and folders generated so far:

luaCopy code
.
│   Dockerfile
│
backend/
│   app.js
│   config.js
│   db.js
│   package.json
│
frontend/
│   package.json
│
└───src/
    │   main.js
    │   App.vue
    │
    ├───components/
    │       TodoList.vue
    │       AddTodo.vue
    │       EditTodo.vue
    │       Splash.vue
    │       Login.vue
    │       Logout.vue
    │
    ├───router/
    │       index.js
    │
    └───store/
            index.js

Dockerfile is added to the root directory to create a Docker image with both the backend and frontend. backend/ contains the Node.js backend with Express, Passport.js for authentication, and SQLite for the database. frontend/ contains the Vue.js frontend application using Vuetify and Vue Router.

To create a Kubernetes deployment for your project, you will need to create a deployment configuration file and a service configuration file.

Create a k8s-deployment.yaml file in the root directory of your project with the following content:

yamlCopy code
apiVersion: apps/v1
kind: Deployment
metadata:
  name: todo-app
spec:
  replicas: 1
  selector:
    matchLabels:
      app: todo-app
  template:
    metadata:
      labels:
        app: todo-app
    spec:
      containers:
        - name: todo-app
          image: your-image-name:latest
          imagePullPolicy: IfNotPresent
          ports:
            - containerPort: 3000
---
apiVersion: v1
kind: Service
metadata:
  name: todo-app
spec:
  selector:
    app: todo-app
  ports:
    - protocol: TCP
      port: 80
      targetPort: 3000
  type: LoadBalancer

Replace your-image-name with the name of your Docker image.

This configuration file includes:

1. A Deployment that defines the desired state for your application, such as the number of replicas, and the container image to use.
2. A Service that exposes the application to external traffic. It maps port 80 on the load balancer to port 3000 on the container.

Before applying the configuration, ensure that you have pushed your Docker image to a container registry accessible by your Kubernetes cluster, such as Docker Hub or Google Container Registry. Update the image field in the deployment configuration to use the correct image path.

To apply the deployment and service configuration, run the following command:

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kubectl apply -f k8s-deployment.yaml

This command will create the deployment and service resources in your Kubernetes cluster. The application should be accessible through the load balancer's external IP address or domain name.