I'm working on a document-based SwiftUI application, and my file contents includes large arrays of doubles. The application involves importing some data from CSV, and then the file saves this data in a data structure.
However, when looking at the file sizes, the custom document type I declare in my application is 2-3 times larger than the CSV file. The other bits of metadata could not possibly be that large.
Here's the JSON output that is saved to file:
Here's the CSV file that was imported:
On looking at the raw text of the JSON output and comparing it with the original CSV, it became obvious that the file format I declare was using a lot of unnecessary precision. How do I make Swift's JSONEncoder only use, for example, 4 decimal places of precision?