You can use standard function StrSplit instead DecomposeStringIntoSubstringsArray.
StrSplit(<String>, <Separator>, <IncludeBlank>)
Character string where every character is an individual delimiter.
Shows if it is required to include the empty strings which can result from a separation of a source string while calculating the result.
Default value: True.
Array with strings resulting from splitting of the source string.
Splits a string into parts according using the specified delimiter.
Thin client, web-client, server, thick client, external connection, Mobile application (client), Mobile application (server).
Arr = StrSplit("aaa,bbb,ccc,ddd", ",");