Is there any solution to export subgrid (expanded grid) rows as csv file?

I’m seeking for a solution to export the sub grid rows as CSV files.

when I try to “Export all sub grid data as csv.” only the header line (super grid data) is downloaded. How can we get all of the sub grid data to get downloaded as a csv.?
If any one familier with grid data, please help me with this.
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Source: AngularJS