index.js

#! /usr/bin/env node
import chalk from 'chalk';
import inquirer from 'inquirer';
//enum define four possible operations
var Operation;
(function (Operation) {
    Operation["ADD"] = "+";
    Operation["SUBTRACT"] = "-";
    Operation["MULTIPLY"] = "*";
    Operation["DIVIDE"] = "/";
})(Operation || (Operation = {}));
// function using switch operation , interface as parameter
function performOperation(input) {
    switch (input.operation) {
        case Operation.ADD:
            return input.firstNumber + input.secondNumber;
        case Operation.SUBTRACT:
            return input.firstNumber - input.secondNumber;
        case Operation.MULTIPLY:
            return input.firstNumber * input.secondNumber;
        case Operation.DIVIDE:
            return input.firstNumber / input.secondNumber;
        default:
            throw new Error(`Invalid operation: ${input.operation}`);
    }
}
// Entry point of application, defines an array of Questioncollection
async function main() {
    const questions = [
        {
            type: 'number',
            name: 'firstNumber',
            message: 'Enter the first number:',
            validate: (input) => input > 0 || 'The number must be greater than 0',
        },
        {
            type: 'number',
            name: 'secondNumber',
            message: 'Enter the second number:',
            validate: (input) => input > 0 || 'The number must be greater than 0',
        },
        {
            type: 'list',
            name: 'operation',
            message: 'Select an operation:',
            choices: [
                { name: 'Addition', value: Operation.ADD },
                { name: 'Subtraction', value: Operation.SUBTRACT },
                { name: 'Multiplication', value: Operation.MULTIPLY },
                { name: 'Division', value: Operation.DIVIDE },
            ],
        },
    ];
    const input = await inquirer.prompt(questions);
    const result = performOperation(input);
    console.log(chalk.green(`The result is: ${result}`));
}
main().catch((error) => console.error(chalk.red(error)));