How to Retrieve Parent ID from Nested JSON Objects in JavaScript

Learn how to efficiently get the immediate `parent ID` of a specific `child ID` in a nested JSON structure using JavaScript.
---
This video is based on the question https://stackoverflow.com/q/62426283/ asked by the user 'Ramyachinna' ( https://stackoverflow.com/u/7373685/ ) and on the answer https://stackoverflow.com/a/62426365/ provided by the user 'trincot' ( https://stackoverflow.com/u/5459839/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: How to get immediate parent Id of the child id in array of nested json Object?

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Understanding Parent-Child Relationships in JSON

Working with nested JSON structures can sometimes be tricky, especially when you need to extract specific relationships, like determining the parent of a given child. This scenario often arises in applications that manage hierarchical data, such as organizational charts or item trees.

In this guide, we'll explore how to get the immediate parent ID of a specific child ID from an array of nested JSON objects using JavaScript. We'll break down the problem, provide a sample JSON structure, and walk through the solution step-by-step.

The Problem

Suppose you have the following nested JSON structure containing entities and their child relationships:

[[See Video to Reveal this Text or Code Snippet]]

In this example, if you want to find the parent ID of the child with entity ID 32, you should receive 6 as the parent ID, and for entity ID 30, you should receive 5.

The Solution: Finding the Parent ID

To achieve this, we can use a recursive function that traverses the JSON structure until it finds our child entity. Once found, we can easily return its parent's ID.

Existing Code Snippet

Here’s a code snippet that was attempted but didn’t quite yield the desired output:

[[See Video to Reveal this Text or Code Snippet]]

This function returns a complete list of IDs in the path back to the root, rather than just the immediate parent ID. The output was:

[[See Video to Reveal this Text or Code Snippet]]

But we want the output to be:

[[See Video to Reveal this Text or Code Snippet]]

Modifying the Code

To modify the code to return only the immediate parent ID, we simply need to adjust the condition under which we push the parent ID into our result array:

Updated Code

[[See Video to Reveal this Text or Code Snippet]]

Summary

Now, with the updated findParent function, calling findParent(arr, 30) will yield [5] and findParent(arr, 32) will yield [6], which is precisely what we want.

Conclusion

Navigating nested JSON structures can be challenging, but with a focused recursive approach, you can effectively extract the relationships you need. The simple modification we made allowed us to refine our function to return only the immediate parent ID, rather than a complete hierarchy.

By following this guide, you should now be equipped to handle similar tasks in your JavaScript applications, efficiently managing parent-child relationships in nested JSON objects.

Happy coding!