[Bug] ECharts splitLine not showing on interval function

[laurentiupomenar]

Version

5.4.3

Link to Minimal Reproduction

https://codepen.io/calabasssita/pen/wvNaJrd

Steps to Reproduce

You can reproduce it also on the examples editor:
There are splitLines under each data label when it's not an empty string:

option = {
  xAxis: {
    type: 'category',
    position: 'top',
    data: ['', 'bbb', '', '', 'aaa', ''],
    splitLine: {
      show: true,
      interval: function(index, value) {
        return value != '';
      }
    }
  },
  dataZoom: [
    {
      type: 'slider'
    }
  ],
  yAxis: {
    type: 'value'
  },
  series: [
    {
      data: [150, 230, 224, 147, 260, 50],
      type: 'line'
    }
  ]
};

Change data do this, for example, the splitLine goes to the left side of the chart, and not under the data label:

 data: ['', '', '', '', 'aaa', ''],

It also happens if you have data like this, and you zoom leaving only one label on the zoomed data

 data: ['', 'bbb', '', '', 'aaa', ''],

Current Behavior

The splitLines does not show under the label when there's only one not empty value in data, it also happens while having more than one not empty values if you zoom the chart so only one one not empty value is shown.

Expected Behavior

To have a splitLine under the data label when it satisfies the function.

Environment

- OS:macOs Ventura 13.4
- Browser: Firefox version 118.0.2 (64-bit)
- Framework:

Any additional comments?

If there's a workaround, to only show the splitLines when a value is different from X it would also help, Thanks.

[helgasoft]

Observations are correct and several bugs are confirmed for interval :

• creates a permanent splitline at the end of the axis, regardless of dataZoom
• creates a splitline at the start of the axis when there is just one axis.data.value!=''
• dataZoom-in shows incorrect splitlines

One partial fix is to use index instead of value - Demo Code

[laurentiupomenar]

Observations are correct and several bugs are confirmed for interval :

* creates a permanent splitline at the end of the axis, regardless of dataZoom

* creates a splitline at the start of the axis when there is just one axis.data.value!=''

* dataZoom-in shows incorrect splitlines

One partial fix is to use index instead of value - Demo Code

Using your demo code and zooming like this also gives the same result

[helgasoft]

That's why I call it "partial fix".

[Ovilia]

There seems to be a bug when there's only one tick. The logic here takes special care about the case with single tick but it assumes the tick is at the start. But in the case of callback, it may not be at the start. I think we should be careful when changing the related logic to make sure we don't break things down. I will look into this later.

[JohnLYYN123]

Here is my fix on the issue and PR link (#19382)

The given data array has only one non-empty value and the rest are empty values