code: function toState (preset) {
    if (preset) {
      const norm = (preset.replace(/[^012345678]/g, "") + "000000000").slice(0, 9)
      const gains = norm.split("").map((n) => Math.abs(+n / 8))
      return {
        bank: { gains }
      }
    }
  }
docs: Given a preset, return a state fragment