code: function range(vars) {
    generation += 1;
    const variables = {};
    const selection = {
      type: 'range',
      generation,
      range: {
        variables,
      },
    };
  
    // Fill variables
    Object.keys(vars).forEach((name) => {
      variables[name] = vars[name].map((interval) =>
        clone(interval, ['interval', 'endpoints', 'uncertainty'], {
          endpoints: '**',
        })
      );
      variables[name].sort((a, b) => a.interval[0] - b.interval[0]);
    });
  
    return selection;
  }
docs: ----------------------------------------------------------------------------