Solving the for Loop Overwrite Issue in PowerShell JSON Arrays

Discover why your PowerShell `for` loop is overwriting JSON objects and learn the effective solution to fix it.
---

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: (PowerShell) Why is the for loop overwriting the JSON objects in the array?

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Understanding the for Loop Overwriting Issue in PowerShell JSON Arrays

PowerShell is a powerful scripting language that allows for efficient data manipulation. However, even seasoned developers can run into issues, like the frustrating problem of a for loop overwriting JSON objects in an array. In this post, we will explore a common scenario that leads to this issue, the mechanics behind it, and a straightforward solution to avoid data overwrite while working with JSON objects.

The Problem

Imagine you have a PowerShell script where you are attempting to populate a JSON object with multiple parameters. The core of the issue lies in this segment of your code:

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

The outcome of this loop is unexpectedly overwriting the values in your $jsonParamObj during each iteration, resulting in all JSON entries reflecting the last input rather than accurately capturing unique values.

Expected vs. Actual Output

Based on your script, the following structure was anticipated:

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

Instead, the actual output was:

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

Why is This Happening?

The crux of the problem is that you are adding the same object reference ($jsonParamObj) to the array on each iteration. As a result, the subsequent updates to the properties of this reference affect all entries in the array rather than creating distinct objects.

The Solution

To resolve this, we need to ensure that a new object is created for every addition to the array during the loop. Here’s how you can modify your loop:

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

Key Notes on the Fix

Use of [pscustomobject]@ { ... }: This syntax is crucial as it generates a new object on each loop iteration, thus preventing references from overlapping.

Maintain Separation of Objects: Each entry in your resulting JSON structure will now reflect the unique attributes of name and des as intended.

Conclusion

In summary, the overwrite issue faced when working with JSON arrays in PowerShell can be resolved by ensuring each entry corresponds to a separate object. Using the [pscustomobject] syntax allows the creation of distinct objects and prevents the pitfalls of mutable references. Implementing this solution will enhance your script's functionality and provide you with the results you expect.

Are there other PowerShell challenges you'd like to tackle? Feel free to drop your questions below!