diff --git a/.github/workflows/php.yml b/.github/workflows/php.yml
index 3455d6c..b32b4ec 100644
--- a/.github/workflows/php.yml
+++ b/.github/workflows/php.yml
@@ -14,7 +14,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        php-versions: ['8.1', '8.2', '8.3', '8.4']
+        php-versions: ['8.1', '8.2', '8.3', '8.4', '8.5']
       fail-fast: false
 
     name: PHP ${{ matrix.php-versions }} Test
@@ -29,7 +29,7 @@ jobs:
         php-version: ${{ matrix.php-versions }}
         tools: composer:v2
         coverage: xdebug
-      continue-on-error: ${{ matrix.php-versions == '8.4' }}
+      continue-on-error: ${{ matrix.php-versions == '8.5' }}
 
     - name: Validate composer.json and composer.lock
       run: composer validate --strict
diff --git a/src/Chart.php b/src/Chart.php
index c4220d0..9d10c7b 100644
--- a/src/Chart.php
+++ b/src/Chart.php
@@ -25,7 +25,7 @@ public function __construct()
     /**
      * Get the chart as an array
      *
-     * @return array
+     * @return array<string, mixed>
      */
     public function get(): array
     {
@@ -35,7 +35,7 @@ public function get(): array
     /**
      * Convert the chart to an array
      *
-     * @return array
+     * @return array<string, mixed>
      */
     public function toArray(): array
     {
@@ -107,10 +107,10 @@ public function beginAtZero(): self
      * Generate the HTML representation of the chart
      *
      * @param string $element
-     * @param Chart $chart
+     * @param Chart|null $chart
      * @return string
      */
-    public function toHtml(string $element, Chart $chart = null): string
+    public function toHtml(string $element, ?Chart $chart = null): string
     {
         if ($chart === null) {
             $chart = $this;
diff --git a/src/ChartInterface.php b/src/ChartInterface.php
index f84ea52..d094f01 100644
--- a/src/ChartInterface.php
+++ b/src/ChartInterface.php
@@ -4,9 +4,15 @@
 
 interface ChartInterface
 {
+    /**
+     * @return array<string, mixed>
+     */
     public function get(): array;
 
     public function toJson(): string;
 
+    /**
+     * @return array<string, mixed>
+     */
     public function toArray(): array;
 }
diff --git a/src/Config/Config.php b/src/Config/Config.php
index 2244799..5e00ed4 100644
--- a/src/Config/Config.php
+++ b/src/Config/Config.php
@@ -4,8 +4,14 @@
 
 class Config implements ConfigInterface
 {
+    /**
+     * @var array<string, mixed>
+     */
     protected array $attributes;
 
+    /**
+     * @param array<string, mixed> $attributes
+     */
     public function __construct(array $attributes = [])
     {
         $this->attributes = $attributes;
@@ -27,40 +33,57 @@ public function &__get($name)
      *
      * @param string $name
      * @param mixed $value
-     * @return $this
+     * @return void
      */
-    public function &__set($name, $value)
+    public function __set($name, $value)
     {
         $this->attributes[$name] = $value;
-
-        return $this;
     }
 
     /**
      * Dynamically set the value of a property.
      *
      * @param string $name
-     * @param mixed $value
+     * @param array<int, mixed> $value
      * @return $this
      */
     public function __call($name, $value)
     {
-        return $this->__set($name, reset($value));
+        $this->__set($name, reset($value));
+
+        return $this;
     }
 
     /**
      * Convert the object to an array.
      *
-     * @return array
+     * @return array<string, mixed>
      */
     public function toArray(): array
     {
         array_walk_recursive($this->attributes, function (&$item) {
-            if (is_object($item)) {
+            if (is_object($item) && method_exists($item, 'toArray')) {
                 $item = $item->toArray();
             }
         });
 
         return $this->attributes;
     }
+
+    /**
+     * @return array<string, mixed>
+     */
+    public function get(): array
+    {
+        return $this->toArray();
+    }
+
+    /**
+     * @return string
+     * @throws \JsonException
+     */
+    public function toJson(): string
+    {
+        return json_encode($this->toArray(), JSON_THROW_ON_ERROR | JSON_HEX_TAG | JSON_HEX_APOS | JSON_HEX_AMP | JSON_HEX_QUOT);
+    }
 }
diff --git a/src/Config/ConfigInterface.php b/src/Config/ConfigInterface.php
index 041e6a4..e877c2d 100644
--- a/src/Config/ConfigInterface.php
+++ b/src/Config/ConfigInterface.php
@@ -4,5 +4,15 @@
 
 interface ConfigInterface
 {
+    /**
+     * @return array<string, mixed>
+     */
+    public function get(): array;
+
+    public function toJson(): string;
+
+    /**
+     * @return array<string, mixed>
+     */
     public function toArray(): array;
 }
diff --git a/src/Config/Options.php b/src/Config/Options.php
index 019e326..4797bb5 100644
--- a/src/Config/Options.php
+++ b/src/Config/Options.php
@@ -2,6 +2,9 @@
 
 namespace Bbsnly\ChartJs\Config;
 
+/**
+ * @method self scales(array<string, mixed> $value)
+ */
 class Options extends Config
 {
 
diff --git a/tests/ChartTest.php b/tests/ChartTest.php
index cd38ff6..8e5c85c 100644
--- a/tests/ChartTest.php
+++ b/tests/ChartTest.php
@@ -526,4 +526,43 @@ private function assertStringNotContains(string $needle, string $haystack): void
             "Failed asserting that '$haystack' does not contain '$needle'"
         );
     }
+    /**
+     * Test if Config class get() and toJson() methods work correctly
+     */
+    public function test_config_get_and_tojson_methods()
+    {
+        $config = new \Bbsnly\ChartJs\Config\Config(['key' => 'value']);
+
+        $this->assertEquals(['key' => 'value'], $config->get());
+        $this->assertEquals('{"key":"value"}', $config->toJson());
+    }
+
+    /**
+     * Regression test for issue #34: `$data->datasets[] = ...; PHP error`.
+     *
+     * Appending to a not-yet-existing magic property must mutate the real
+     * underlying array. This relies on Config::&__get() returning the
+     * attribute by reference. Without it PHP raises
+     * "Indirect modification of overloaded property ... has no effect"
+     * (which PHPUnit turns into a failure) and the append is silently lost.
+     */
+    public function test_it_can_append_to_a_magic_array_property()
+    {
+        $data = new Data();
+
+        // Property does not exist yet — append must create and grow the array.
+        $data->datasets[] = (new Dataset)->data([10, 20, 30]);
+        $data->datasets[] = (new Dataset)->data([30, 20, 10]);
+
+        $this->assertCount(2, $data->datasets);
+        $this->assertEquals(
+            [
+                'datasets' => [
+                    ['data' => [10, 20, 30]],
+                    ['data' => [30, 20, 10]],
+                ],
+            ],
+            $data->toArray()
+        );
+    }
 }