Stem Direction

There are a few ways to set stem direction in VexFlow.

• To auto-format the stem (determines direction based on staff line), pass an auto_stem property on StaveNote creation:

It's important to note, that you must correctly pass in the clef property, otherwise auto-stemming will not behave accurately

var note = new Vex.Flow.StaveNote({
    clef: 'bass',
    keys: ['f/3'],
    duration: '4',
    auto_stem: true
});

• To set the direction yourself, pass a stem_direction property on creation

var note = new Vex.Flow.StaveNote({
    keys: ['c/5'],
    duration: '4',
    stem_direction: Vex.Flow.StaveNote.STEM_UP // (or STEM_DOWN)
});

• You can also get/set the stem direction of a note after it's been created:

var down = Vex.Flow.StaveNote.STEM_DOWN;
note.setStemDirection(down)
note.getStemDirection() // returns -1 -- the value of STEM_DOWN