Værditab af bil baseret på satser fra https://www.dr.dk/nyheder/saa-hurtigt-falder-din-nye-bil-i-vaerdi

index.js

const cliTable = require('cli-table')

function calc(purchaseValue, entryYear, numYears) {
    const table = new cliTable({
        head: ['Periode', 'Bilens værdi', '%', 'Værditab i alt', '%', 'Årets værditab', 'Årets værditab pr. mnd', 'Ydelse pr. mnd over hele perioden'],
        colWidths: [9, 14, 4, 16, 4, 16, 24, 35]
    })

    const percentualValueEachYear = [100, 81, 67, 56, 48, 39, 34, 29, 25, 22, 19, 18, 16].slice(entryYear)
    // If entryYear is 0, 19, 14, 11, 8, 9, 5, 5, 4, 3, 3, 1, 2
    const percentualLossEachYear = percentualValueEachYear.map((value, index, arr) => (arr[index - 1] || 100) - value)
    const computedPercentageValues = percentualValueEachYear.map((value, index) => value + percentualLossEachYear[0])

    for (let i = 0; i < numYears; i++) {
        const valueLastYear = purchaseValue * (computedPercentageValues[i] / 100)
        const valueThisYear = purchaseValue * (computedPercentageValues[i + 1] / 100)
        const valueThisYearPct = computedPercentageValues[i + 1]
        const accumulatedLoss = purchaseValue - valueThisYear
        const yearlyLoss = valueLastYear - valueThisYear
        const monthlyLoss = yearlyLoss / 12
        const months = (i + 1) * 12

        table.push([
            months + ' mnd.',
            formatNumber(Math.round(valueThisYear)),
            valueThisYearPct,
            formatNumber(Math.round(accumulatedLoss)),
            100 - computedPercentageValues[i + 1],
            formatNumber(Math.round(yearlyLoss)),
            formatNumber(Math.round(monthlyLoss)),
            formatNumber(Math.round(accumulatedLoss / months))
        ])
    }

    return table.toString()
}

function formatNumber(num) {
    const x = String(num).split('.')
    const x2 = x.length > 1 ? ',' + x[1] : ''
    const rgx = /(\d+)(\d{3})/
    let x1 = x[0]

    while (rgx.test(x1)) {
        x1 = x1.replace(rgx, '$1' + '.' + '$2')
    }
    return x1 + x2
}

function logExample(purchaseValue, manufactureYear, thisYear = 2018) {
    console.log('Årgang', manufactureYear, '- købspris', formatNumber(purchaseValue) + ',-')
    console.log(calc(purchaseValue, thisYear - manufactureYear, 5))
    console.log()
}

logExample(220000, 2018)
logExample(220000, 2017)
logExample(220000, 2016)
logExample(220000, 2015)