SingleValueData.value might be undefined

[beigert]

When you call 

```

const singleValue = convertToSingleValueData({
  indexRange: [0, 0],
  mappings: { x: { type: 'undefined', types: undefined } },
}, 0,{ x: undefined } "x", true);

if (single.value === undefined) // ESLint: Unnecessary conditional, the types have no overlap.(@typescript-eslint/no-unnecessary-condition)

Result of `convertToSingleValueData` looks like:

export interface SingleValueData {
    /** The dimension identifier */
    dimension: string;
    /** The value for the dimension */
    value: string | number;
    /** The timeseries for the sparkline */
    timeseries?: TimeseriesWithDimensions[];
}

value is typed as a string or number, however is not true, and it might be undefined as well.

[michalbrabec · Accepted solution]

Hello, thank you for pointing it out. We will check it and fix it.