other_usage.org

json2nd - other usage scenarios

If what we find isn’t an array:

A JSON value other than an array will just be extracted un-modfied, except we’ll stick a newline on the end, and remove any newlines from within the record.

Check we’re unpacking an array

The main use case of this tool is to unpack arrays, but as NDJSON can be any type we don’t raise an error if this is called with something other than array. However, you can apply the -expect-array flag to have json2nd check that whatever we’re processing is an array.

echo "{}" | json2nd -expect-array > object.json # will error

Stream of things

Say you have a stream of JSON sperated by whitespace, probably newlines (sounds like NDJSON eh?) but your objects may have been pretty printed so won’t actually work as NDJSON.

printf "{\n}\n{} {\n} 1234" | json2nd # output will be valid NDJSON

One caveat at this time is that if you hit an array json2nd will error, because it’s default behaviour with respect to arrays conflicts with what’s expected here. If you are expecting a JSON stream that may contain arrays you probably want to use the -preserve-array switch.

A cheap value finder

Although not it’s true purpose:

json2nd -path thing.i.want file.json

is quite easy to remember when you want to grab any old thing from some json.