code: function modf (float) {
    const i = Math.trunc(float)
    const f = Math.abs(float - i)
    return [i, f]
  }
docs: separate fix `i` from fraction `f`
  @private
  @param {Number} float
  @returns {Array} [i, f]
  {Number} i - (int) fix value
  {Number} f - (float) fractional portion; always > 1