Error when including Ionic PWA toolkit app

[ni-ka]

Trying to use this component in https://github.com/ionic-team/ionic-pwa-toolkit

Not sure the error is on this side but I am getting this error as soon as I import in one of my pages (import { WebAudio } from 'web-audio-wc';)

TypeError: Cannot read property 'querySelectorAll' of null
at Object.attachStyles (app.core.js:361)
at render (app.core.js:876)
at renderUpdate (app.core.js:997)
at update (app.core.js:991)
at push (app.core.js:952)
at elm.s-rc.forEach.cb (app.core.js:886)
at Array.forEach ()
at render (app.core.js:886)
at renderUpdate (app.core.js:997)
at update (app.core.js:991) 8 "WEB-AUDIO"