Last Updated: 2024-12-03

Some quick notes on dealing with binary data on the web:

• very often base64 is used.
• there are functions to encode (btoa)/ decode (atob) unicode (often ASCII) input as base64
• e.g. btoa is in HTML standard (it is in most browsers but not in React Native) The input data must be in the form of a string containing only characters in the range from U+0000 to U+00FF, each representing a binary byte with values 0x00 to 0xFF.
• The naming is confusing in that btoa stands for "binary to ascii" and atob is ascii to binary. THe In practice both the input and output of these functions are Unicode strings. What differs is whether one outputs base64 or note - this being considered ascii.
• Encoding data in base64 is not without some costs - it can take up 30% more space and slow down both sender and receiver When you want to upload a file with a JSON apis, an easy way to do this is to encode the file as a base64 string and just put it right in the JSON (e.g. "{photo: "afAKSDKFK..."}". This avoids any need for multipart/form-data