Combine multiple json documents into one encrypted document and decrypt with javascript

I have an win form application that collects json documents from a directory and combines them into a 1GB file. We need to be able to encrypt the content before writing it to the file. We need to be able to decrypt it with a javascript function. The js function needs to decrypt the content and read the variables into our mobile app.

We really just want to stop our competition from easily downloading our data and easily reading our documents. The json documents contain a large volume of coordinates for a mapping software so encrypting the numbers is the most important part.

The json document is in the following format

const jsonDocuments = {'file_name1','filename2'...};
// content of document 1
const filename1 = {};
// content of document2
const filename2 = {};

The final code would have to be supplied as a function for our form application as well as a decrypt function for javascript.