The interpolatingNulls property determines whether to interpolate null values in the data.
If true, the chart interpolates the value of any missing data based on neighboring points. If false, it leaves a break in lines and areas at the points with null values.
For line and area charts, you can display gaps in the data as empty by setting this property to false.
Example:
import * as chart from '@grapecity/wijmo.chart';
var myChart = new chart.FlexChart('#myChart');
myChart.interpolateNulls = false;