Extract Objects
Extracts one value, or a list of values, from a JSON object or array with a JSONPath query.
The Extract Objects action reads a JSON object, a JSON array or a data model and pulls out the values that match a JSONPath query. You get both the first match and the full list of matches, so one action covers "give me this field" and "give me every item that…".
Extract Objects was previously called JSON Mapper. It replaces the older Extract List action, which is being decommissioned: the Result List output gives you the same list.
Add the action
In the Process Designer toolbox, open JSON and pick Extract Objects (or type Extract Objects in the search box).
Inputs and outputs
| Field | Direction | Type | Required | What to put / what you get |
|---|---|---|---|---|
| Input JSON | Input | JSON | Yes | The JSON object, JSON array or data model to read. You can type it or use a variable. |
| Query | Input | Text | Yes | A JSONPath expression, for example $.store.book[*].title. |
| Result | Output | Any type | No | The first value that matches the query. Empty when nothing matches. |
| Result List | Output | List of any type | No | Every value that matches the query. An empty list when nothing matches. |
Example
Input JSON:
{
"store": {
"book": [
{ "title": "Sapiens", "price": 8.5 },
{ "title": "Dune", "price": 12, "isbn": "0-441" }
],
"bicycle": { "color": "red" }
}
}| Query | Result | Result List |
|---|---|---|
$.store.bicycle.color | red | ["red"] |
$.store.book[*].title | Sapiens | ["Sapiens", "Dune"] |
$..book[?(@.price < 10)] | {"price": 8.5, "title": "Sapiens"} | [{"price": 8.5, "title": "Sapiens"}] |
$.store.car (no match) | empty | [] |
With a JSON array as input, for example [{"name":"Eric","amount":122.45},{"name":"Chris","amount":144.99}], the query $..name returns Result Eric and Result List ["Eric", "Chris"].
Good to know
- Result always holds the first match, even when the query matches several values. Use Result List when you need all of them.
- A query that matches nothing does not fail the step: Result stays empty and Result List is
[]. - If Input JSON is not a JSON object or array, the step fails with
The input is not a valid JSON/JArray. - If the query is not valid JSONPath (for example
$[[), the step fails with the JSONPath parser's message. - Matched values keep their JSON type: a number stays a number and an object stays an object. Map Result to a variable of the type you expect.
Related actions
- String To JSON, Key Value, JSON Is Valid
- Mapper, the same idea for XML with XPath