How do you get the index of a given string in a sequence of strings?

[binarykitchen]

This seems to be missing ... thanks for any hints

[hallettj]

There is an undocumented function keepIndexed that you can use in this fashion:

const kept = mori.keepIndexed((idx, string) => string === referenceString ? idx : null, strings)
const matchingIndex = mori.first(kept)

[binarykitchen]

thanks @hallettj but why is it undocumented?

[hallettj]

I don't know why keepIndexed is not documented. I happened to get a pretty good look at that and other unadvertised functions while assembling type definitions for Mori.