Incubator-echarts: xaxis type=time labels do not reflect series data

[gajus]

Version

4.3.0

Reproduction link

https://codesandbox.io/s/echarts-xaxis-time-ef3e3

Steps to reproduce

1. create xaxis type=time
2. populate series with date range from 2019-10-01 to 2019-10-31

What is expected?

I expect labels to be dates from "2019-10-01 00:00" to "2019-10-31 00:00".

What is actually happening?

Last label is "2019-10-30 23:00" instead of "2019-10-31 00:00".

[susiwen8]

Last label is "2019-10-31 00:00"

[gajus]

Not when I view it.

Using Chrome latest version on macos.

[Ovilia]

This may be a bug related to time-zone. @gajus Could you tell us what your time-zone is?

[gajus]

Eastern European Summer Time

[gajus]

This shouldn't say waiting-for: author anymore.

[Ovilia]

Thanks for your update. Let's see if we can get this fixed in 4.6.0.
BTW, if you're interested in making a pull request, that would be perfect because it may be easier for you to reproduce this problem. Please let us know if you need some help on this.

[devyumao]

Eastern European Summer Time is a daylight saving time zone with which different browsers handle in different ways, e.g., the timestamp 1572469200000 in Firefox is equivalent to '2019-10-31 00:00', but in Chrome it is '2019-10-30 23:00'.
I'm not sure whether this is a bug. Hereby to let you know. @100pah

[100pah]

@devyumao Chrome and Firefox are the same in my computer for new Date(1572469200000),
they are both Wed Oct 30 2019 23:00:00 GMT+0200 (Eastern European Standard Time)

[100pah]

@gajus
By default, echarts uses local timezone to formate time labels.
But if we set timezone to Eastern European, there would be
Eastern European Summer Time issue, as @devyumao said.

The boundary of Eastern European Summer Time and Eastern European Standard Time is:

new Date(1572137999999)
Sun Oct 27 2019 03:59:59 GMT+0300 (Eastern European Summer Time)
new Date(1572137999999 + 1)
Sun Oct 27 2019 03:00:00 GMT+0200 (Eastern European Standard Time)

In your case, the time axis is from Oct 1 to Oct 31, which crosses the boundary (about Oct 27),
so the time labels look weird.

So, the option useUTC is recommended in your case:

option = {
    useUTC: true,
    xAxis: {...},
    yAxis: {...}
    series: {
        ...
    }
}

If you are using string-formatted time in data (for example, "2019-10-01"),
we do not need to convert the time to UTC, it's OK to keep the current time data.
The useUTC just make sure all of the string time formatted in consistent way.

[Ovilia]

Closed due to not-a-bug.