Legend value for null series value

[nickofthyme]

Describe the bug
When hovering over a split group, if a given series in the legend does not have a value for that split group, the last value will show is the legend only for that series, and others with no values too. This results in a possible mixture of last and current values.

Also if a series does not have a "last" value the closest to last value is used, making the value entirely confusing!

To Reproduce
Steps to reproduce the behavior:

1. Create BarSeries

// playground.tsx
import React from 'react';

import { Axis, Chart, getAxisId, getSpecId, niceTimeFormatter, Position, ScaleType, Settings, BarSeries } from '../src';
import { KIBANA_METRICS } from '../src/utils/data_samples/test_dataset_kibana';
import { CursorEvent } from '../src/specs/settings';
import { CursorUpdateListener } from '../src/chart_types/xy_chart/store/chart_state';

const DATA = [
  {
    'extension.keyword': '',
    'geo.src': 'IN',
    count: 23,
  },
  {
    'extension.keyword': '',
    'geo.src': 'CN',
    count: 17,
  },
  {
    'extension.keyword': '',
    'geo.src': 'US',
    count: 6,
  },
  {
    'extension.keyword': '',
    'geo.src': 'BR',
    count: 3,
  },
  {
    'extension.keyword': '',
    'geo.src': 'FR',
    count: 3,
  },
  {
    'extension.keyword': 'gz',
    'geo.src': 'CN',
    count: 9,
  },
  {
    'extension.keyword': 'gz',
    'geo.src': 'US',
    count: 5,
  },
  {
    'extension.keyword': 'gz',
    'geo.src': 'IN',
    count: 4,
  },
  {
    'extension.keyword': 'gz',
    'geo.src': 'BD',
    count: 3,
  },
  {
    'extension.keyword': 'gz',
    'geo.src': 'AR',
    count: 2,
  },
  {
    'extension.keyword': 'css',
    'geo.src': 'CN',
    count: 7,
  },
  {
    'extension.keyword': 'css',
    'geo.src': 'VE',
    count: 3,
  },
  {
    'extension.keyword': 'css',
    'geo.src': 'IN',
    count: 2,
  },
  {
    'extension.keyword': 'css',
    'geo.src': 'US',
    count: 2,
  },
  {
    'extension.keyword': 'css',
    'geo.src': 'AF',
    count: 1,
  },
  {
    'extension.keyword': 'zip',
    'geo.src': 'CN',
    count: 8,
  },
  {
    'extension.keyword': 'zip',
    'geo.src': 'IN',
    count: 7,
  },
  {
    'extension.keyword': 'zip',
    'geo.src': 'US',
    count: 4,
  },
  {
    'extension.keyword': 'zip',
    'geo.src': 'PH',
    count: 2,
  },
  {
    'extension.keyword': 'zip',
    'geo.src': 'BD',
    count: 1,
  },
  {
    'extension.keyword': 'deb',
    'geo.src': 'CN',
    count: 5,
  },
  {
    'extension.keyword': 'deb',
    'geo.src': 'SA',
    count: 3,
  },
  {
    'extension.keyword': 'deb',
    'geo.src': 'IT',
    count: 2,
  },
  {
    'extension.keyword': 'deb',
    'geo.src': 'PK',
    count: 2,
  },
  {
    'extension.keyword': 'deb',
    'geo.src': 'CG',
    count: 1,
  },
];

export class Playground extends React.Component {
  render() {
    return (
      <Chart>
        <Settings tooltip={{ type: 'vertical' }} debug={false} legendPosition={Position.Right} showLegend />
        <Axis id={getAxisId('timestamp')} title="timestamp" position={Position.Bottom} />
        <Axis id={getAxisId('count')} title="count" position={Position.Left} tickFormat={(d) => d.toFixed(2)} />
        <BarSeries
          id={getSpecId('Testing')}
          xScaleType={ScaleType.Ordinal}
          yScaleType={ScaleType.Log}
          data={DATA}
          xAccessor="extension.keyword"
          yAccessors={['count']}
          splitSeriesAccessors={['geo.src']}
        />
      </Chart>
    );
  }
}

1. Hover over the first bucket
2. Notice the legend value of AR is 2.00 which AR has no value for the first bucket.

Expected behavior
The current value should always be shown and if there is no current value a - (dash) or similar should be used to indicate the absence of a value.

Screenshots

Kibana Cross Issues
Add any Kibana related issues here.

Checklist

• every related Kibana issue is listed under Kibana Cross Issues list
• kibana cross issue tag is associated to the issue if any kibana cross issue is present

[markov00]

That should be already fixed in the last master version 11.0.3
@nickofthyme could you check? I'm pretty sure it's fixed

[nickofthyme]

Ok let me check.

[nickofthyme]

@markov00 You are correct! I still think the mixed values for the "last" value is problematic so I commented on the discuss ticket #246 (comment)