What libraries or functions, internal or external, does Elisp use to extract fields from JSON?

Does Emacs have good libraries for extracting fields from JSON values? Are there some libraries which demonstrate good working examples of these?

Emacs comes with a JSON parsing library: [Parsing JSON](https://www.gnu.org/software/emacs/manual/html_node/elisp/Parsing-JSON.html) I don't know a good place for examples but to start you off, json-parse-string parses JSON from a string into an elisp hash table, which you can access with gethash: (gethash "hello" (json-parse-string "{\"hello\": \"world\"}")) -> "world" [Hash Access](https://www.gnu.org/software/emacs/manual/html_node/elisp/Hash-Access.html)

You can also change the type of object you get back from hash-table to alist, and then use the wonderful get-alist macro the navigate the file contents. This is good for smaller JSON, the bigger what you are parsing the more you benefit from the faster hash-tables.

I have had a go at this and it is all good.