Function levels

docs/tests/v2/es6/js/sanddance.js:111897–111900

(values, f, _)

};

function levels(values, f, _) {
  const q = (0, _quantize.default)(_.levels || 10, _.nice, _.zero !== false);
  return _.resolve !== 'shared' ? q : q(values.map(t => (0, _d3Array.max)(f(t).values)));
}

function transform(grid, scale) {
  const x1 = grid.x1 || 0,