feat(function): Create function that checks for the existence of a specific key within a hash table.

Author: SamErde

General/Test-HashTableKeyEsistence.ps1

@@ -0,0 +1,71 @@
+function Test-HashTableKeyExistence {
+<#
+    .SYNOPSIS
+    Check if a key exists in a hash table.
+
+    .DESCRIPTION
+    This function checks whether a specified key exists in a hash table, even if the associated value is $null.
+
+    .PARAMETER HashTable
+    The hash table to check. Accepts input from the pipeline.
+
+    .PARAMETER KeyToCheck
+    The key to check for existence in the hash table.
+
+    .INPUTS
+    Hashtable: accepts hashtable object from the pipeline.
+    String: accepts key name as a string.
+
+    .OUTPUTS
+    Boolean: Returns true if the key exists, false otherwise.
+
+    .EXAMPLE
+    $HashTable = @{
+        Key1 = 'Value1'
+        Key2 = $null  # Note: this key exists but has null value
+        Key3 = 'Value3'
+    }
+    Test-HashTableKeyExistence -HashTable $HashTable -KeyToCheck 'Key2'
+
+    Tests if 'Key2' exists in the provided hash table.
+
+    .EXAMPLE
+    $HashTable = @{
+        KeyA = 'ValueA'
+        KeyB = 'ValueB'
+    }
+
+    $HashTable | Test-HashTableKeyExistence -KeyToCheck 'KeyC'
+
+    Tests if 'KeyC' exists in the provided hash table.
+
+    .NOTES
+    Author: Sam Erde
+    Version: 1.0
+    Date: 2026-01-05
+#>
+    [CmdletBinding()]
+    [OutputType([bool])]
+    param (
+
+        # The hash table object to check.
+        [Parameter(Mandatory = $true, ValueFromPipeline = $true)]
+        [ValidateNotNull()]
+        [hashtable]$HashTable,
+
+        # The name of the key to check.
+        [Parameter(Mandatory = $true)]
+        [ValidateNotNullOrEmpty()]
+        [string]$KeyToCheck
+    )
+
+    process {
+        if ($HashTable.ContainsKey($KeyToCheck)) {
+            Write-Verbose "The key [$KeyToCheck] exists in the hash table."
+            $true
+        } else {
+            Write-Verbose "The key [$KeyToCheck] does not exist in the hash table."
+            $false
+        }
+    }
+}