5 Ways to Comment Your JSON

Posted on

Comments aren’t part of the official JSON specification. According to an old (2012) Google Plus post by Douglas Crockford, he removed them to preserve interoperability.  But that same post suggests you can still use comments  so long as you remove them through minification before parsing.

There are a few other ways to handle JSON comments besides minification:

  1. You can add a new data element to your object. The element key would be named  “_comment_” or something similar. The value would be the actual comment. This method is slightly intriguing but feels kind of dirty. It looks like a hack. It is a hack! bulk is also added to the network payload. JSON is a lightweight data exchange. Adding comment elements takes away from this.
  2. Use Scripts that programmatically remove comments from your JSON before it’s parsed. Sindre Sorhus published a comment stripping module which does just that. This is similar to Crockord’s method of minification in that it removes the comments before parsing but you can inline it in your code rather than use it during a build process.
  3. You can forget comments in your JSON entirely. Put comments in the code where you make the data request in the first place. You should already know what kind of returned data is expected so comments would make sense here. You can stay in your code without the need to view a separate file. This makes your code easier to understand.
  4. Finally, if JSON is being used as a configuration file or some other static data store, you might even try commenting it in a separate file. Put a text README in the same directory the configuration file is stored. The README could contain a paragraph describing the data or you could copy the JSON into the README and use inline comments.

There are several ways to take care of the problem of commenting JSON files. All have their strengths and weaknesses. The best method depends on your particular situation and needs.