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.
Try to find the original form of a verb, and the names for the (series of) conjugations of the passed verb form.