What problem does this feature solve?

set interval on e-chart of type 'time', there is no to set interval against only day or month or year independently.

Set interval should show axis equally after that specific interval like if we give the interval difference of 4 years only then next each date of axis must be after 4 years even if leap is there.

I want interval gap must be same if give 4 years interval or in days, Months or collectively.

consider the below link for code analysis and implementation.
http://jsfiddle.net/d7e09r5t/274/

What does the proposed API look like?

xAxis : [
       {
           type: 'time',
           boundaryGap:true,
           interval:null, 
           axisLabel: {
               formatter: (function(value){
               dates.push(value);
                   return moment(value).format('DD/MM/YYYY');
               })
           }
       }
   ],

consider the below link for code analysis and implementation.
http://jsfiddle.net/d7e09r5t/274/