add startValue and endValue parameters in zoom event triggered by slider

What problem does this feature solve?

When user uses slider to zoom the chart, the event triggered does not have parameters startValue and endValue. It only has start and end percentage values.

What does the proposed API look like?

Version

4.2.1

Reproduction link

https://www.echartsjs.com/examples/en/editor.html?c=line-simple

Steps to reproduce

• Please copy the following code into input on the left side.

option = {
    title: {
        text: 'ECharts 入门示例'
    },
    tooltip: {},
    legend: {
        data:['销量']
    },
    xAxis: {
        data: ["衬衫","羊毛衫","雪纺衫","裤子","高跟鞋","袜子"]
    },
    yAxis: {},
    series: [{
        name: '销量',
        type: 'line',
        data: [5, 20, 36, 10, 10, 20]
    }],
    dataZoom: [
        {
            type: 'slider',
            show: true,
            realtime: false
        },    
    ]
};

myChart.on('dataZoom', function (params) {
    console.log(params);
    
    // should return exact values, but returns undefined
    console.log(params.startValue);
    console.log(params.endValue);
});

• Then try to zoom the chart and have a look at console.

What is expected?

As described in the docs, datazoom event includes startValue and endValue in the payload if the event is triggered by using toolbox. But I think the datazoom event (triggered by the slider) should also take parameters startValue and endValue besides start and end percentage parameters.

What is actually happening?

startValue and endValue parameters are not included in the payload of the event.

Thank you.

[DhrubajitPC]

+1 any updates on this?

honestly, the solution at https://stackoverflow.com/questions/42503988/echarts-datazoom-event-does-not-return-timestamp-but-only-percentages/43910746#43910746 feels like an unnecessary workaround

[umutcanbolat]

Hi @Ovilia! I’m already aware of this note. My purpose is to see the same values not only in datazoom event triggered by toolbox, but also in the event triggered by the slider.