Having a hard time finding third party library in Ionic 2 - module not found

Having a hard time finding third party library .js file with ionic 2, I’m getting “module not found”. All though I have installed it by typing “npm install progressbar.js”. My home.ts has the correct import statement: “import * as ProgressBar from ‘progressbar.js’;”, and the progressbar.js folder is under node_modules folder.