getPertChange.js

export function getPertChange(breakdown, num_days) {

    const change = (breakdown[breakdown.length - 1].value -
                    breakdown[breakdown.length - 1 - num_days].value)
                    / breakdown[breakdown.length - 1- num_days].value
   
    // Change %
    const pert_change = change * 100;

    // Round off to first digit after decimal
    return Math.round(pert_change * 10) / 10

}