1 /**

     2  * @param {number} start

     3  * @param {number=} stop

     4  * @param {number=} step

     5  */

     6 d3.range = function(start, stop, step) {

     7   if (arguments.length < 3) {

     8     step = 1;

     9     if (arguments.length < 2) {

    10       stop = start;

    11       start = 0;

    12     }

    13   }

    14   if ((stop - start) / step == Infinity) throw new Error("infinite range");

    15   var range = [],

    16        i = -1,

    17        j;

    18   if (step < 0) while ((j = start + step * ++i) > stop) range.push(j);

    19   else while ((j = start + step * ++i) < stop) range.push(j);

    20   return range;

    21 };