test

const test = (p, seed) => {
    let a = 'abcdefghijklmnopqrstuvwxyz'
    let r = ''
    let i = 0
    for (const c of seed) {
        if (p.length === i) {
            i = 0
        }
        if (c !== ' ') {
            // increase 
            // r += a[a.indexOf(c) + parseInt(p[i]) >= 26 ? Math.abs((a.indexOf(c) + parseInt(p[i])) - 26) : a.indexOf(c) + parseInt(p[i])]
            // decrease
            r += a[a.indexOf(c) - parseInt(p[i]) < 0 ? Math.abs((a.indexOf(c) - parseInt(p[i])) + 26) : a.indexOf(c) - parseInt(p[i])]
        } else {
            r += ' '
        }
        i++
    }
    return r
}