Reducing JSON with jq

Question

I have a JSON array of Objects:

[{key1: value},{key2:value}, ...]

I would like to reduce these into the following structure:

{key1: value, key2: value, ...} 

Is this possible to do with jq?

I was trying:

cat myjson.json | jq '.[] | {(.key): value}'

This doesn't quite work as it iterates over each datum rather than reducing it to one Object.

Answer 1

Note that jq has a builtin function called 'add' that the same thing that the first answer suggests, so you ought to be able to write:

jq add myjson.json

Answer 2

To expand on the other two answers a bit, you can "add" two objects together like this:

.[0] + .[1]

=> { "key1": "value", "key2": "value" }

You can use the generic reduce function to repeatedly apply a function between the first two items of a list, then between that result and the next item, and so on:

reduce .[] as $item ({}; . + $item)

We start with {}, add .[0], then add .[1] etc.

Finally, as a convenience, jq has an add function which is essentially an alias for exactly this function, so you can write the whole thing as:

add

Or, as a complete command line:

jq add myjson.json