dygraphs: Allow null in DataArray (#41193)
dygraphs: Allow null in DataArray (#41193)

See for example http://dygraphs.com/gallery/#g/independent-series
georgemarshall/DefinitelyTyped,markogresak/DefinitelyTyped,georgemarshall/DefinitelyTyped,georgemarshall/DefinitelyTyped,mcliment/DefinitelyTyped,dsebastien/DefinitelyTyped,dsebastien/DefinitelyTyped,georgemarshall/DefinitelyTyped