toCodys.js

#!/usr/bin/env node

const [n, u] = process.argv.slice(2);
const t = parseFloat(n);

function kelvin(value) {
    const sunK = 5778.0;
    const sunCodys = 1_000_000_000.0;

    return (value / sunK) * sunCodys;
}

function celsius(value) {
    const k = value + 273.15;

    return kelvin(k);
}

function fahrenheit(value) {
    const c = (value - 32.0) * (5.0 / 9.0);

    return celsius(c);
}

switch (u) {
case 'k':
case 'K':
    console.log(kelvin(t).toLocaleString(), "Codys");
    break;
case 'c':
case 'C':
    console.log(celsius(t).toLocaleString(), "Codys");
    break;
case 'f':
case 'F':
    console.log(fahrenheit(t).toLocaleString(), "Codys");
    break;
}