> ## Documentation Index
> Fetch the complete documentation index at: https://docs.zeotap.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Scenario 3: Extraction of Object Data Using a Custom Transformer

To extract a particular property from the incoming List (Array) of Objects as a separate field in your Catalogue, you can utilise this transformation. In the below example, under the **properties** column, you can observe that objects with properties such as create date, email, first name and more are ingested. To extract and identify a particular property like first name as an individual field in the catalogue, you can utilise this custom transformation. Here, you need to use the directive, `JSON-Path` for your requirement.

<Frame>
  <img src="https://mintcdn.com/zeotap/htBST1bc1LEJ85Nd/articles/unify-customer/Storage/unify-customer/scenario-3-extraction-of-object-data-using-custom-transformer/scenario-3-extraction-of-object-data-using-custom-transformer-2024-07-08.png?fit=max&auto=format&n=htBST1bc1LEJ85Nd&q=85&s=014a4e4aa351e70daf146d5f81025a34" alt="" width="2806" height="974" data-path="articles/unify-customer/Storage/unify-customer/scenario-3-extraction-of-object-data-using-custom-transformer/scenario-3-extraction-of-object-data-using-custom-transformer-2024-07-08.png" />
</Frame>

**Syntax**

`json-path <source-column> <destination-column> <expression>`

* `<source-column>` specifies the column in the record that should be considered as the "root member object" or "\$"
* `<destination-column>` is the name of the output column in the record where the results of the expression will be stored
* `<expression>` is a JSON path expression; see *Usage Notes* below for details

An expression always refers to a JSON structure in the same way that an XPath expression is used in combination with an XML document. The "root member object" is always referred to as \$ regardless if it is an object or an array.

### Use Case: Extracting First Name from Ingested Object Data in Zeotap CDP

Assume that you have ingested an “Object” type data into Zeotap CDP that has a property, *First name*, which needs to be extracted as a new field in your Catalogue. Here, you can use the directive JSON Path to extract the required field as mentioned below.

#### Directives for Data Transformation

```bash Code theme={null}
set-column dataFields json:Parse(dataFields)
json-path dataFields firstName '$[?(@.key == "firstName")].value'
flatten :firstName
```

<Note>
  **Note:**

  For more information on this directive, JSON Path. refer [here](https://github.com/data-integrations/wrangler/blob/develop/wrangler-docs/directives/json-path.md).
</Note>

Below are details of how each directive functions:

| **Directive**                                                       | **Description**                                                                                                                  |
| :------------------------------------------------------------------ | :------------------------------------------------------------------------------------------------------------------------------- |
| `set-column dataFields json:Parse(dataFields)`                      | Parses the `dataFields` column into a JSON format, facilitating easier manipulation and extraction of data.                      |
| `json-path dataFields firstName '$[?(@.key == "firstName")].value'` | Uses JSON Path to locate the `firstName` key within the `dataFields` JSON object and extracts its corresponding value.           |
| `flatten :firstName`                                                | Ensures that the `firstName` field is flattened into a simple, single-level structure, ready for further processing or analysis. |