Function to return all string and cdata of XMLTag.innerXML

[sophiebremer]

Is your feature request related to a problem? Please describe.
Combining all inner strings and cdata of an XMLTag to a text string is cumbersome.

Describe the solution you'd like
A utility function getTextContent would accept an XMLTag and return the text string of all XMLTag.innerXML.

Describe alternatives you've considered
Array.join() is not good enough to cover nested strings.

Additional context
A similar implementation can be found for DOM's Node.textContent.