Leveraging the Browser Database
The browser has become a powerful and grossly under used tool. This site is an example of that power.  I build searches in the browser.  This is supposed to be impossible. It gives me the power to leverage my imagination.  It permits me to search by weighted context.  I can also provide search against multiple sources that appear to the user as a single search.  It reduces my cost. I run this site on $8/month.
As of this writing, 7.22.23, FireFox is by far the fastest implementation for indexedDB. This is the nonSQL database residing inside every browser.
The current amount of available space per database is 2GB as of 2020. I can't find later specs. I believe this is arbitrary. The entire space for indexedDB is half of the available space of the disk drive.
We can do a tremendous amount of work with this amount of space. Examples for text would be from Data is Plural.
There are different routes we can take in this discussion. A browser with a local server. In this case we would be loading files within the server space.  A second would be the first option while using MongoDB.  There are other databases one can use but I am not going to cover the breath of this topic.
MongoDB is a great tool. You can use it locally or in the cloud. Do not use the MongoDB installation guide. Use the Digital Ocean guide. On the other hand the courses at Mongo U are very good and free.
Pulling info from two sources at the same time and making them look like one source. This includes accumulating the search in the browser. Which is supposed to be impossible.
Finding Scholarly Experts.