Recently, Programmers are more inclined towards creating web application with AJAX than doing it with static HTML pages which makes applications faster and richer. But by doing so, application loses its indexability which results in modern and user friendly yet less searchable apps.
One more way to do it is using CRAWLME middleware which makes your .js files indexable by search engines, a copyright of Optimal Bits Sweden AB.
($ npm install crawlme)
To read more on how to install and implement CRAWLME, read our blog: How to Use CRAWLME