derive ‘intercalate’ from ‘concat’, ‘empty’, and ‘reduce’

[davidchambers]

@syaiful6 first proposed this function in March 2017 (sanctuary-js/sanctuary#360). @masaeedu opened a pull request to add the function in June 2018 (sanctuary-js/sanctuary#569). Let's finally define intercalate in January 2020. :)

[Avaq]

I like it! Will it replace https://sanctuary.js.org/#joinWith eventually?

[davidchambers]

Will it replace https://sanctuary.js.org/#joinWith eventually?

Good question. I like having S.joinWith (s) as the inverse of S.splitOn (s), and I'm not opposed to including a specialization of another Sanctuary function if its type signature is significantly simpler. In fact, I believe we should add your combinators to Sanctuary: although duplicative, they would provide significant pedagogical value and (soon) useful search results.

[Avaq]

they would provide significant pedagogical value and (soon) useful search results

That might work. But do we really want to increase the API surface to improve search results? Maybe for the website we could implement some sort of "search-only aliases".

• We have the combinators that map to several existing functions
• We have the Ramda dictionary which maps to Sanctuary functions
• And now we have specialized functions which have been generalized and renamed

All of these could make use of a search-only mapping, where if a user types unnest or flatten they might find join, and if they type String -> Array String -> String or joinWith they might find intercalate.