translateToAbcjs.js

const NAME_COMMON = ["", "C", "C+", "D", "E-", "E", "F", "F+", "G", "A-", "A", "B-", "B"];

// C2 ^C2 _E2 =E2 ^F2 G2 A2 _B2 c2|
// ^: sharp
// =: natural
// =: flat
function translateToAbcjs(scaleBySemitone){
    console.log(scaleBySemitone)
    const outArr = []
    const changedNotes = []
    for(let each of scaleBySemitone){
        console.log(each)

        const nameIndex = each > 12 ? each - 12 : each
        const octave = each > 12 ? 1 : 0
        console.log("octave", octave)

        const note = (_ => {
            if(octave == 0){
                return NAME_COMMON[nameIndex].substr(0, 1)
            } else if(octave == 1){
                return NAME_COMMON[nameIndex].substr(0, 1).toLowerCase()
            }
        })()

        const postfix = NAME_COMMON[nameIndex].substr(NAME_COMMON[nameIndex].length-1, 1)
        console.log(note, postfix)
        if(note.toUpperCase() != postfix){
            const prefix = postfix == "+" ? "^" : "_"
            changedNotes.push(note)
            outArr.push(prefix + note + "2")
        } else {
            if( changedNotes.indexOf(note) != -1 ){
                outArr.push("=" + note + "2")
            } else {
                outArr.push(note + "2") 
            }
        }

    }
    console.log(outArr)
    return outArr.join(" ")
}