Solving Nested Array Transformation Issues with JOLT in JSON

Discover how to effectively use `JOLT` transformations to handle nested arrays in JSON. Learn the steps and specifications to achieve your desired output.
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Understanding JOLT Transformations for Nested Arrays in JSON

Handling JSON data transformation can often be tricky, especially when dealing with nested arrays. One such common challenge occurs when you need to restructure JSON data to fit a specific output format. In this guide, we will explore a case study involving a JOLT transformation issue where a nested array needs to be modified, and we’ll provide practical solutions to achieve this.

The Problem Scenario

Imagine you have the following JSON input structure:

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This input needs to be transformed into the following format:

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However, the current JOLT specification being used does not produce the desired results. Let's take a deeper look into how we can resolve this issue.

Crafting the Correct JOLT Specification

To achieve the required output format, we can utilize a shift transformation with JOLT. Below is the suggested transformation specification:

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Breakdown of the Specification

"id": "&": This line essentially means to keep the root id as is.

"Item": This dictates how the Item array will be processed.

* is a wildcard that matches any index in the Item array.

The inner structure processes each Item, extracting both ID and characteristics.

Nested Transformation for Characteristics:

**"char*"**: Matches any characteristic starting with "char".

Using @ value pulls the value associated with the characteristic and maps it to the target output.

Alternate Specification for Different Output

If you want to create a different output structure where only char1 is returned for the first object, while char1 and char2 are returned for subsequent objects, you can use this specification:

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Conclusion

Handling nested arrays with JOLT transformations can indeed be a daunting task, but with the right specifications and approaches, you can achieve your desired output structure effectively. By following the breakdown and using the examples provided, you can customize your JSON transformations to flow smoothly with your data requirements.

If you ever face issues with JOLT transformations, specifically with nested arrays, refer back to this guide to streamline your process!