series.data() does not return whitespace data

[varunsavaliya]

Lightweight Charts™ Version:

Steps/code to reproduce:

• Add one chart with candlestick data and another chart with line series data.
• Add 100 data in both the series but here the catch is, the first 10 data's value is undefined in line series and candlestick data will be normal data.
• Now try to get the data using seriesApi.data() of line series and candlestick series.
• You'll get 100 data in the candlestick series which is usual behavior but in the line series you'll only get 90 data, it's automatically removing undefined data while getting data from the series using seiesApi.data().
• Now, the issue is, that it is creating a break in the syncing of 2 charts which I am attaching new 100 data in both series. i.e. old 100 data(from series) + new 100 data.

Here, assume that the below function is used for updating series data. I'll pass new data and it will add it before the existing data.

handleData = (series: ISeriesApi<SeriesType>, data: any) => {
  series.setData([...data, ...series.data()])
}

Actual behavior:

• I am setting 100 data in series with 10 undefined values in data. seriesApi.data() is returning only 90 data excluding 10 undefined data.

Expected behavior:

• seriesApi.data() should return all actual data with undefined value if any. i.e. If I set 100 data in series with 10 undefined values then seriesApi.data() should return me 100 data with 10 undefined.

[edew]

Thanks for the detailed report @varunsavaliya

We will investigate how we can improve this.

[edew]

I believe this is happening because we filter whitespace data in these places.

lightweight-charts/src/model/data-layer.ts

Line 336 in 2bb4154

this._seriesRowsBySeries.set(series, seriesRows.filter(isSeriesPlotRow));

lightweight-charts/src/model/get-series-plot-row-creator.ts

Line 119 in 2bb4154

export function isSeriesPlotRow(row: SeriesPlotRow | WhitespacePlotRow): row is SeriesPlotRow {

[varunsavaliya]

I found one temporary solution for this:
You can pass NaN instead of undefined. it will not filter the data as the function only filters if the value is undefined.

lightweight-charts/src/model/get-series-plot-row-creator.ts

Line 120 in 2bb4154

return (row as Partial<SeriesPlotRow>).value !== undefined;

Here we can do one thing, we can remove this undefined check. But, it may have some impact on other functionalities. Instead, we can pass a flag in series.data(someFlag) for including whitespace data.