Add '-AsArray' parameter to 'ConvertoTo-Json' command (#6438)

Add `-AsArray` parameter to `ConvertoTo-Json` command to always pack the output string in array brackets, even if the input is a single object.

src/Microsoft.PowerShell.Commands.Utility/commands/utility/WebCmdlet/ConvertToJsonCommand.cs

@@ -61,9 +61,18 @@ namespace Microsoft.PowerShell.Commands
         /// be converted to their string equivalent. Otherwise, enum values
         /// will be converted to their numeric equivalent.
         /// </summary>
-        [Parameter()]
+        [Parameter]
         public SwitchParameter EnumsAsStrings { get; set; }
 
+        /// <summary>
+        /// Gets or sets the AsArray property.
+        /// If the AsArray property is set to be true, the result JSON string will
+        /// be returned with surrounding '[', ']' chars. Otherwise,
+        /// the array symbols will occur only if there is more than one input object.
+        /// </summary>
+        [Parameter]
+        public SwitchParameter AsArray { get; set; }
+
         #endregion parameters
 
         #region overrides
@@ -104,7 +113,7 @@ namespace Microsoft.PowerShell.Commands
         {
             if (_inputObjects.Count > 0)
             {
-                object objectToProcess = (_inputObjects.Count > 1) ? (_inputObjects.ToArray() as object) : (_inputObjects[0]);
+                object objectToProcess = (_inputObjects.Count > 1 || AsArray) ? (_inputObjects.ToArray() as object) : (_inputObjects[0]);
                 // Pre-process the object so that it serializes the same, except that properties whose
                 // values cannot be evaluated are treated as having the value null.
                 object preprocessedObject = null;

test/powershell/Modules/Microsoft.PowerShell.Utility/ConvertTo-Json.Tests.ps1

@@ -35,4 +35,17 @@ Describe 'ConvertTo-Json' -tags "CI" {
         $ps.InvocationStateInfo.State | Should -BeExactly "Stopped"
         $ps.Dispose()
     }
+
+    It "The result string is packed in an array symbols when AsArray parameter is used." {
+        $output = 1 | ConvertTo-Json -AsArray
+        $output | Should -BeLike "``[*1*]"
+
+        $output = 1,2 | ConvertTo-Json -AsArray
+        $output | Should -BeLike "``[*1*2*]"
+    }
+
+    It "The result string is not packed in the array symbols when there is only one input object and AsArray parameter is not used." {
+        $output = 1 | ConvertTo-Json
+        $output | Should -BeExactly '1'
+    }
 }