Deconjugation? conconjugation? Anyway, this module lets you generate verb conjugation lists, as well as try to unconjugate a vern form to its original verb.
npm install jp-conjugation
var verbs = require('jp-conjugation');
.conjugate(verb, verbtype) -> array
generate the verb conjugations. If the verb is ambiguously ichidan or nidan, adding verbtype "v1" will force conjugation as an ichidan verb.
.unconjugate(verb)
Try to find the original form of a verb, and the names for the (series of) conjugations of the passed verb form.