This package provides the typescript types for nody-greeter and web-greeter.
npm install nody-greeter-types
import {lightdm, theme_utils} from "nody-greeter-types";
lightdm.authentication_complete.connect(() => console.log("DONE!"));
theme_utils.dirlist("/usr/share/backgrounds", true, (files) => {
console.log(files);
});