fix(cmdlets): 🐛 update input handling and line splitting

* Refactored `_inputObjectBuffer` handling in `TextMateCmdletBase` to use `TextMateHelper.SplitToLines`.
* Improved `NormalizeToLines` method to handle multiline strings more effectively.
* Added a new test case to validate splitting of multiline pipeline items in `Format-CSharp`.
* Updated demo image path in README for consistency.

Author: trackd

README.md

@@ -9,7 +9,7 @@ What it does
 - Provides discovery and testing helpers for installed grammars, extensions, or language IDs.
 - Does inline Sixel images in markdown
 
-![Demo](/assets/demo.png)
+![Demo](./assets/demo.png)
 
 ## Cmdlets
 

src/Cmdlets/TextMateCmdletBase.cs

@@ -101,7 +101,7 @@ protected override void ProcessRecord() {
                     EnsureSourceHints();
                 }
 
-                _inputObjectBuffer.Add(inputString);
+                _inputObjectBuffer.AddRange(TextMateHelper.SplitToLines(inputString));
             }
         }
         else if (InputObject is not null) {
@@ -142,7 +142,7 @@ protected override void EndProcessing() {
     }
 
     private HighlightedText? ProcessStringInput() {
-        string[] lines = TextMateHelper.NormalizeToLines(_inputObjectBuffer);
+        string[] lines = [.. _inputObjectBuffer];
 
         if (lines.AllIsNullOrEmpty()) {
             WriteVerbose("All input strings are null or empty");

src/Utilities/Helpers.cs

@@ -36,28 +36,28 @@ static TextMateHelper() {
             throw new TypeInitializationException(nameof(TextMateHelper), ex);
         }
     }
-    internal static string[] NormalizeToLines(List<string> buffer) {
-        if (buffer.Count == 0) {
-            return [];
+    internal static string[] SplitToLines(string input) {
+        if (input.Length == 0) {
+            return [string.Empty];
         }
 
-        // Multiple strings in buffer - treat each as a line
-        if (buffer.Count > 1) {
-            return [.. buffer];
+        if (input.Contains('\n') || input.Contains('\r')) {
+            return input.Split(["\r\n", "\n", "\r"], StringSplitOptions.None);
         }
 
-        // Single string - check if it contains newlines
-        string? single = buffer[0];
-        if (string.IsNullOrEmpty(single)) {
-            return single is not null ? [single] : [];
+        return [input];
+    }
+
+    internal static string[] NormalizeToLines(List<string> buffer) {
+        if (buffer.Count == 0) {
+            return [];
         }
 
-        // Split on newlines if present
-        if (single.Contains('\n') || single.Contains('\r')) {
-            return single.Split(["\r\n", "\n", "\r"], StringSplitOptions.None);
+        var lines = new List<string>(buffer.Count * 2);
+        foreach (string item in buffer) {
+            lines.AddRange(SplitToLines(item));
         }
 
-        // Single string with no newlines
-        return [single];
+        return [.. lines];
     }
 }

tests/Format-CSharp.tests.ps1

@@ -2,6 +2,8 @@ BeforeAll {
     if (-Not (Get-Module 'TextMate')) {
         Import-Module (Join-Path $PSScriptRoot '..' 'output' 'TextMate.psd1') -ErrorAction Stop
     }
+
+    Import-Module (Join-Path $PSScriptRoot 'testhelper.psm1') -Force
 }
 
 Describe 'Format-CSharp' {
@@ -32,6 +34,16 @@ Describe 'Format-CSharp' {
             Remove-Item -Force -ErrorAction SilentlyContinue $temp
         }
     }
+
+    It 'Splits multiline pipeline items into individual lines' {
+        $s1 = "// a`npublic class A { }"
+        $s2 = "// b`npublic class B { }"
+
+        $out = @($s1, $s2) | Format-CSharp
+
+        $out.LineCount | Should -Be 4
+    }
+
     It 'Should have Help and examples' {
         $help = Get-Help Format-CSharp -Full
         $help.Synopsis | Should -Not -BeNullOrEmpty

tests/testhelper.psm1

@@ -16,7 +16,7 @@ function _GetSpectreRenderable {
         $console = [AnsiConsole]::Create($settings)
         $console.Write($RenderableObject)
         if ($EscapeAnsi) {
-            return $writer.ToString() | _EscapeAnsi
+            return [Host.PSHostUserInterface]::GetOutputString($writer.ToString(),$false)
         }
         $writer.ToString()
     }