Post-hyphenation of split compound words

Question

Assuming that these two words

off-topic

on-topic

must be hyphenated, which of the punctuations in the following sentences is correct? (crucial part emphasized)

Regardless of whether it is an off or on-topic example, it is a brilliant consideration in the definition of this proposal.

Regardless of whether it is an off- or on-topic example, it is a brilliant consideration in the definition of this proposal.

I know you can get around this with a verbose constuction like off-topic or on-topic, or by not hyphenating either and treating off and on and topic as separate words, but neither suggestion really does anything to answer my question.

Answer 1

The standard way to deal with this in English is your second example, off- or on-topic. Another example of where the hyphen would be preserved for both forms of the hyphenated word might be pre- and post-, eg.

The pre- and post-match responses of the soccer fans were markedly different.