export function abstract (chords, tonic) {
tonic = pc(tonic)
chords = map(parse, chords)
var tonics = compact(chords.map(function (x) { return x.tonic }))
// if some tonic missing, can't do the analysis
if (tonics.length !== chords.length) return null
return tonics.map(function (t, i) {
var p = props(interval(tonic, t))
return buildRoman(p.num - 1, p.alt, chords[i].type)
})
}
return function (tonic) {
return compact(map(tr(tonic || 'P1'), list))
}
export function harmonics (list) {
var a = asArr(list)
return a.length ? compact(a.map(interval(a[0]))) : a
}