Seeing that there was yet another way to query & transform JSON that I hadn’t heard of, I wanted to collect all the ways to do just that for future reference

JSON Path

Wikipedia states that

JSONPath is a query language for querying values in JSON. The uses of JSONPath include Selecting a specific node in a JSON value
Retrieving a set of nodes from a JSON value, based on specific criteria
Navigating through complex JSON values to retrieve the required data.

There is an online evaluator you can play with over here. The biggest difference to the other two seems to me the lack of any functions to perform e.g. arithmetics.

jq

jq is a nice little command line tool to perform selections and transformations over json. I used the tool here to get to some information about failed jest tests. You can try an online version of the tool for funsies.

If you take as an example this simple JSON…

{
  "shoppingCart": {
    "items": [
      {
        "category": "fiction",
        "title": "The Great Adventure",
        "price": 10,
        "quantity": 2
      },
      {
        "category": "non-fiction",
        "title": "Learn JSON",
        "price": 20,
        "quantity": 1
      },
      {
        "category": "science",
        "title": "Physics Basics",
        "price": 15,
        "quantity": 3
      }
    ],
    "totalPrice": 100
  }
}

The query

[.shoppingCart.items[] | .price * .quantity] | add

will select price and quantity of each object in the items array, multiply them, and add them together.

JSONata

I had never heard about this until today. JSONata can also do querying, transforming and arithmetic, and manages so with a pretty simple syntax. Given the same example from above, the correct query to also get a total sum looks like this:

$sum(shoppingCart.items.(price * quantity))

This tool also provides an online playground to check it out.

Which one do you prefer?