A simple command line todo app running on Node

todo.js

// run from command line
// saves todo to file, appending it
// also displays data, highlighing high, medium, and low priority tasks

// Examples:

// node todo.js --add --todo="brush teeth"
// node todo.js --display

const fs = require('fs');
const parseArgs = require('minimist');
const chalk = require('chalk');

const todoFile = 'todo.txt'

const addTodoToFile = (todo, priority='Medium') => {
    fs.appendFile(todoFile, `${priority}: ${todo} \n`, (err) => {
        if (err) throw err;
        console.log('Todo was added');
      });
}

const addTodo = (args) => {
    const {todo, priority} = args
    addTodoToFile(todo, priority)
}

const highlightTodo = (todoLine) => {
    const [priority, todo] = todoLine.split(": ")
    switch (priority) {
        case 'High': 
            return chalk.red(todo)
        case 'Medium':
            return chalk.yellow(todo)
        case 'Low':
            return chalk.green(todo)
    }
}

const displayTodos = () => {
    try {
        console.log(chalk.greenBright('****** TODAY\'S TODOS ********'))
        const stream = fs.createReadStream(todoFile)
        const lineReader = require('readline').createInterface({
            input: stream
        });
        lineReader.on('line', (line) => {
            console.log(highlightTodo(line));
        });
        //lineReader.on('close', () => console.log('That\'s it!'))
    } catch (err) {
        if (err.includes('ENOENT')) {
            console.log('Nothing to display. Please add a todo first')
        }
        
    }
   
} 

/* we expect { 
    _: [], 
    'add'|'display': true, 
    todo: todoText, 
    priority:'Low'|'Medium'|'High' 
}
todo is required if run is 'add', and priority defaults to Medium
*/

const args = parseArgs(process.argv.slice(2));
if (args.add) {
    addTodo(args)
} else if (args.display) {
    displayTodos();
} else {
    console.log('ERROR: not a valid command;')
}