calc.js

//create a CLI for user
const operations = require('./operations.js');
const readline = require('readline');


//use realine to create command line interface
const rl = readline.createInterface({
	input: process.stdin,
	output: process.stdout,
});

console.log(`
	Calc.js

	Welcome to the Nodejs Calculator app!
	V: 1.0.0.

	Usage: The user will be prompted for two numbers,
	then asked to select their operation of choice.
	`);

rl.question('Enter the first number: ', x => {
  rl.question('Enter the second number: ', y => {
    rl.question(
      `
    Please select from the following options:
    [1] Addition (+)
    [2] Subtraction (-)
    [3] Multiplication (*)
    [4] Division (/)
    Enter your choice: `,
      choice => {
        if (!operations.validateNumbers(x, y)) {
          console.log('Only numbers are allowed! Please restart the program.')
        } else {
          switch (choice) {
            case '1':
              console.log(`The sum of ${x} and ${y} is ${operations.add(x, y)}.`)
              break
            case '2':
              console.log(`The difference of ${x} and ${y} is ${operations.subtract(x, y)}.`)
              break
            case '3':
              console.log(`The product of ${x} and ${y} is ${operations.multiply(x, y)}.`)
              break
            case '4':
              console.log(`The quotient of ${x} and ${y} is ${operations.divide(x, y)}.`)
              break
            default:
              console.log('Please restart the program and select a number between 1 and 4.')
              break
          }
        }
        rl.close()
      }
    )
  })
})

//exit
rl.close();