Scribbletune

npm install scribbletune

Let's put something together. Create a file called chords.js and paste the following in it,

const scribble = require('scribbletune');
  const clips = ['1032', '2032', '4021', '3052'].map(order =>
    scribble.clip({
      pattern: '[xx][xR]'.repeat(4),
      notes: scribble.arp({
        chords: 'Dm BbM Am FM BbM FM CM Gm',
        count: 8,
        order,
      }),
      accent: 'x-xx--xx',
    })
  );
  scribble.midi([].concat(...clips), 'chords.mid');

Now execute that file in the terminal at the same location as you saved it,

node chords.js

This will generate a MIDI file called chords.mid in the same location as you executed this script. You can import this file into any music production software like Ableton Live or even Garage Band! Here's how it sounded when I did that and rendered it with a couple of synths and the same chords on a pad sound: