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Image encoding in Node JS

This article is work in progress!

While programming on a side project, I had to deal with images in a node application. My application is using Express, Amazon Rekognition as well as Pouchdb.

I was dealing with different sources & targets:

  • A user uploads a picture
  • I read a picture from file, be it in JPEG or PNG format
  • I send a picture to AWS
  • I store a picture in my pouchDB

While browsing the different sources, I encountered various formats on how images can be handled in node:

  • As buffer containing binary data
  • As string conatining Base64 encoded data, starting with something like data:image/jpeg;base64, (or with png)
  • As string containing base64 encoded data without the special beginning

These are the different operations I am doing and what they provide as output:

  • Reading a file from disk with fs: return a Bufferwith binary data

These are the sources and targets in/from which image data is transferred in my example: Image sources and targets

Reading

Helpful stuff I found about the topics: