Solution for the isAdmissibleOverpayment challenge in code signal

isAdmissibleOverpayment.js

function isAdmissibleOverpayment(prices, notes, x) {
    const difference = prices.reduce((sum, currentPrice, index) => {
        const percentageChange = parsePercentageFromNote(notes[index]);
        const originalPrice = reversePercentage(currentPrice, percentageChange);
        // difference between the prices
        return sum = sum + currentPrice - originalPrice;
    }, 0);
    return difference.toPrecision(5)  <= x;
}

// reverse percentage implementation
function reversePercentage(currentPrice, percentageChange) {
    // (1) Work out the current price as a percentage of the original price
    const percentageFromOriginalPrice = 100 + percentageChange;
    // (2) Find 1% by dividing the current price
    const onePercent = currentPrice / percentageFromOriginalPrice;
    // (3) Multiply this 1% by 100 to find the original price
    return onePercent * 100;
}

// get the percentage from the text note
function parsePercentageFromNote(note) {
    const tokens = note.split(' ');
    if (tokens[0] === 'Same') {
        return 0
    }
    const multipier = tokens[1] === 'higher' ? +1 : -1;
    return multipier * parseFloat(tokens[0]);
}