Support for monthly time axis labels

What problem does this feature solve?

When I create a time axis which the values are on a monthly basis, echarts creates labels in Y-M-D format, which I’d expect Y-M format. See this JSFiddle: https://jsfiddle.net/up0hq4zL/

Data is like:

"data": [
    ["2019-01", "400"],
    ["2019-02", "500"],
    ["2019-05", "600"],
]

And the outcome is:

And this is the proposed look:

Normally I could make this happen using the xAxis.axisLabel.formatter function; however the timestamps it receives don’t correspond to the first day of each month. For example it receives a timestamp for “2019-03-25” which I wouldn’t format as YEAR-MONTH because that would mislocate March tick on the x axis because you’d think a tick would mark the beginning of the month.

[xiaoyvr]

Month is not a fixed interval. using category will not work if we need an accurate axis.

I’d suggest to add this kind of support or provide a way to customize the split behavior.

[pissang]

Hi, @maliayas

I’d suggest using category type axis. And fill the month missing data with value '-'