Simple Task Manager CLI using Node.js

Before creating a simple Task Manager CLI using NodeJS, let’s run our first basic Node.js application with the following simple steps:

Note: You can download and install the Node.js application from href=”https://nodejs.org/en/”
Step 1: Create a Directory for our Task Manager CLI named TODO-CLI, you can give the name of your choice.

write  :  mkdir <filename>

Step 2: In that directory make a JavaScript file named index.js as shown below:

Make  an index.js file 

Step 3: This file contains some JavaScript code to run a program, Now we can write some sample code as shown below:

Step 4: After writing the code in the index.js file run this file using the following command:

node index.js

After running the command you will the following output So, now we confirm that our index.js file is running without any problem.

Step 5: Install the following modules which are used for this application using the following command:

npm install yargs
npm install lodash

• loadsh: A modern JavaScript utility library that helps to work with Array, Numbers, String, Objects, and Strings.
• yargs: It is an interactive command-line module that helps to read the user input. 

Step 6: Create a new file called todo.js and write down the following code in it:

Filename: todo.js

Javascript

console.log("todo.js is running !!");

const fs = require('fs');

// Add a todo item
var addTodo = (title) => {
    var todos = fetchTodos();
    var todo = {
        title
    };

    var duplicatetodos = todos.filter(
        (todo) => todo.title === title);

    if (duplicatetodos.length === 0) {
        todos.push(todo);
        saveTodos(todos);
        return todo;
    }
};

// Delete a todo item
var deleteTodo = (title) => {
    var todos = fetchTodos();
    var filteredtodos = todos.filter(
        (todo) => todo.title !== title);
    saveTodos(filteredtodos);

    return todos.length !== filteredtodos.length;
};


// Read a todo item
var readTodo = (title) => {
    var todos = fetchTodos();
    var filteredTodos = todos.filter(
        (todo) => todo.title === title);
    return filteredTodos[0];
};


// List all todo items
var listTodos = () => {
    return fetchTodos();
};


// Utility functions
var fetchTodos = () => {
    try {
        var todosString =
            fs.readFileSync('tasks-data.json');
        return JSON.parse(todosString);
    } catch (e) {
        return [];
    }
};

var saveTodos = (todos) => {
    fs.writeFileSync('tasks-data.json',
        JSON.stringify(todos));
};

var logTodo = (todo) => {
    console.log('## ---## --- ##');
    console.log(`It's title is: ${todo.title}`);
};

// Exporting function
module.exports = {
    addTodo,
    deleteTodo,
    readTodo,
    listTodos,
    logTodo
};

In the above file included in the utility section which handles all the NodeJS file management system like shown below: 

•  readFileSync: https://www.geeksforgeeks.org/node-js-fs-readfilesync-method/
•  writeFileSync: https://www.geeksforgeeks.org/node-js-fs-writefilesync-method/
•  JSON.parse: https://www.geeksforgeeks.org/javascript-json-parse-method/
•  JSON.stringify: https://www.geeksforgeeks.org/javascript-json-stringify-method/

Step 7: Now update our previous index.js file code with the following complete code:

Filename: index.js

Javascript

console.log("index.js is running");

const fs = require('fs');
const _ = require('lodash');
const yargs = require('yargs');

const tasks = require('./todo');

const argv = yargs.argv;

var command = argv._[0];
console.log('Running Command is :', command);

if (command === 'addTodo') {
    tasks.addTodo(argv.title);
} else if (command === 'deleteTodo') {
    var todoDeleted = tasks.deleteTodo(argv.title);
    var message = todoDeleted ?
        'Todo was deleted' : 'Todo can not found';
    console.log(message);
} else if (command === 'readTodo') {
    var todo = tasks.readTodo(argv.title);
    if (todo) {
        console.log('yahoo! The todo was found.');
        tasks.logTodo(todo);
    } else {
        console.log('Oops! The todo was not found.');
    }
} else if (command === 'listTodos') {
    var allTodos = tasks.listTodos();
    console.log(`${allTodos.length} tasks available`);
    allTodos.forEach((todo) => tasks.logTodo(todo));
} else {
    console.log('It is a Invalid command.');
}

Step 8: Following are some command for our Task Application:

1. Add Tasks: Use the following command to add tasks for our application.

node index.js addTodo --title="your tasks"  

When you add all the tasks by the use of the command line, if you look at the project folder you can see a task-data.json file is create and all the tasks are listed as JSON structure in that file as shown below:

2. Delete Tasks: Delete task is necessary when completed the tasks and you wanted to delete from your tasks list, you can delete task using the following command:

node index.js deleteTodo --title="your task"  

When you run this command, if you point out in the task-data.json you see which data you typed to delete it remove from the tasks list as shown below:

3. Read Tasks: If you wanted to check your all tasks are present or not, use the following command:

node index.js readTodo --title="your task"  

4. Display List of Tasks: If you want to see all tasks which not yet completed, then use the following command:

node index.js listTodos