Change: improve the implementation of spaceless

_config/config.yml

@@ -10,3 +10,7 @@ SilverStripe\Core\Injector\Injector:
         spaceless: ['\Moo\Template\Parser\Spaceless', 'spaceless']
       openBlocks:
         content: ['\Moo\Template\Parser\TemplateBlock', 'content']
+
+SilverStripe\ORM\FieldType\DBString:
+  extensions:
+    - Moo\Template\Extension\SpacelessCast

src/Template/Extension/SpacelessCast.php

@@ -0,0 +1,29 @@
+<?php
+
+namespace Moo\Template\Extension;
+
+use Moo\Template\Parser\Spaceless;
+use SilverStripe\Core\Extension;
+use SilverStripe\ORM\FieldType\DBField;
+
+class SpacelessCast extends Extension
+{
+    private static array $casting = [
+        'Spaceless' => 'HTMLText',
+    ];
+
+    /**
+     * Get string without extra spaces.
+     */
+    public function Spaceless(): DBField
+    {
+        return DBField::create_field(
+            'HTMLText',
+            Spaceless::spaceless([
+                'Template' => [
+                    'php' => $this->getOwner()->RAW(),
+                ],
+            ])
+        );
+    }
+}

src/Template/Parser/Spaceless.php

@@ -7,28 +7,124 @@
  */
 class Spaceless
 {
+    /**
+     * Remove space from the start of the statement.
+     */
+    protected static array $patternStart = [
+        '/\'(\s+)([^\s\'])/m',
+        "'$2",
+    ];
+
+    /**
+     * Remove space from between HTML tags.
+     */
+    protected static array $patternBetweenTag = [
+        '/>\s+</',
+        '><',
+    ];
+
+    /**
+     * Remove space from the end of the statement.
+     */
+    protected static array $patternEnd = [
+        '/([^\s\'])(\s+)\';/m',
+        "$1';",
+    ];
+
+    /**
+     * Convert multiple spaces into one space.
+     */
+    protected static array $patternOneSpace = [
+        '!\s+!',
+        ' ',
+    ];
+
+    /**
+     * Remove space from empty statement `$val .= '  ';`.
+     */
+    protected static array $patternEmpty = [
+        '/\'(\s+)\';/m',
+        "'';",
+    ];
+
     /**
      * Remove white spaces from around template code.
      *
-     * @param $res
-     * @return null|string|string[]
+     * @param array $res
+     *
+     * @return ?string
      */
     public static function spaceless($res)
     {
-        // Pattern to find whitespaces
+        // Template string code to remove whitespaces from
+        $php = $res['Template']['php'];
+
+        // Convert into an array
+        $code = static::toStatementPerLine($php);
+
+        // Clean up each i  tem in the array
+        $index = 0;
+        foreach ($code as $key => $line) {
+            $code[$key] = static::cleanCode((string) $line, $index);
+            ++$index;
+        }
+
+        return implode("\n", $code);
+    }
+
+    /**
+     * Clean up a line of code based on its position `$index`.
+     */
+    protected static function cleanCode(string $value, int $index): string
+    {
+        // Default replacements
         $pattern = [
-            '/\'(\s+)([^\s\'])/m',
-            '/\'(\s+)\'/m',
-            '/([^\s\'])(\s+)\';/m',
-            '/>\s+</',
+            static::$patternEnd[0],
+            static::$patternOneSpace[0],
+            static::$patternEmpty[0],
+            static::$patternBetweenTag[0],
         ];
 
-        // Template string code to remove whitespaces from
-        $php = $res['Template']['php'];
+        $replacement = [
+            static::$patternEnd[1],
+            static::$patternOneSpace[1],
+            static::$patternEmpty[1],
+            static::$patternBetweenTag[1],
+        ];
+
+        // Replacements for first line of code
+        if ($index === 0) {
+            $pattern = [
+                static::$patternStart[0],
+                static::$patternEnd[0],
+                static::$patternOneSpace[0],
+                static::$patternEmpty[0],
+                static::$patternBetweenTag[0],
+            ];
 
-        // Remove whitespaces
-        $php = preg_replace($pattern, ["'$2", "''", "$1';", '><'], $php);
+            $replacement = [
+                static::$patternStart[1],
+                static::$patternEnd[1],
+                static::$patternOneSpace[1],
+                static::$patternEmpty[1],
+                static::$patternBetweenTag[1],
+            ];
+        }
+
+        return preg_replace($pattern, $replacement, $value);
+    }
+
+    /**
+     * Convert the PHP string into an array of items. One statement per line.
+     */
+    protected static function toStatementPerLine(string $value): array
+    {
+        // Convert string into single line string
+        $value = str_replace(["\r\n", "\n", "\r", "\t"], '', $value);
+        // Add break-line before every start of a statement `$val .=`
+        $value = str_replace('$val .=', "\n\$val .=", $value);
 
-        return $php;
+        // Convert the string into an array item per line
+        return array_filter(explode("\n", $value));
     }
 }