Creating/Writing/Downloading Files in NestJS

Working on a project, I realized there was no proper way mentioned anywhere on how we can create/write/download file functions in NestJS. So today, I am going to mainly show you the way I approach to it.

If you are new to my articles, please be sure to refer to my other article Best Way to Structure Your Directory/Code (NestJS), which I am going to use in this post as well.

We are going to take example of CSV generation (User exports) for this article.

Note: This article is not about uploading a file. For that, everything is mentioned in the NestJS Docs.

storage.helper.ts

This file contains some helper functions related to reading & writing files using fs package. You can also put all these in a separate StorageService but I like to keep them separate & make them globally available for use so that I don’t have to inject them all the time.

users.service.ts

The UsersService mainly contains all the business logic related to the User…