[Enhancement] Reactive options as closure for multi-select prompt

- Accepted options argument as closure
  - Turned options property to mixed type as it might hold the closure
  - Passed values property to the closure for reactivity; just like validate method
- Added an evaluatedOptions property for caching until it's set to null
  - Created options method that evaluates, caches and returns the options all around
    - Threw an exception when all options are no longer available
    - Removed previously selected options from values when they're gone
    - Adjusted the indexing
- Introduced a new "toggle" state to re-render without errors
  - Set the evaluatedOptions to null (resetting cache and evaluation) for toggle and error states
- Tested for closure, reactivity, and the empty options exception
  - Ensured all tests are passing

src/MultiSelectPrompt.php

@@ -2,7 +2,9 @@
 
 namespace Laravel\Prompts;
 
+use Closure;
 use Illuminate\Support\Collection;
+use Laravel\Prompts\Exceptions\NonInteractiveValidationException;
 
 class MultiSelectPrompt extends Prompt
 {
@@ -11,9 +13,16 @@ class MultiSelectPrompt extends Prompt
     /**
      * The options for the multi-select prompt.
      *
-     * @var array<int|string, string>
+     * @var array<int|string, string>|Closure(array<int|string, string>): array<int|string, string>|Collection<int|string, string>
      */
-    public array $options;
+    public mixed $options;
+
+    /**
+     * The evaluated options cache.
+     *
+     * @var array<int|string, string>|null
+     */
+    public ?array $evaluatedOptions = null;
 
     /**
      * The default values the multi-select prompt.
@@ -32,12 +41,12 @@ class MultiSelectPrompt extends Prompt
     /**
      * Create a new MultiSelectPrompt instance.
      *
-     * @param  array<int|string, string>|Collection<int|string, string>  $options
+     * @param  array<int|string, string>|Collection<int|string, string>|Closure(array<int|string, string>): array<int|string, string>|Collection<int|string, string>  $options
      * @param  array<int|string>|Collection<int, int|string>  $default
      */
     public function __construct(
         public string $label,
-        array|Collection $options,
+        array|Collection|Closure $options,
         array|Collection $default = [],
         public int $scroll = 5,
         public bool|string $required = false,
@@ -51,16 +60,42 @@ public function __construct(
         $this->initializeScrolling(0);
 
         $this->on('key', fn ($key) => match ($key) {
-            Key::UP, Key::UP_ARROW, Key::LEFT, Key::LEFT_ARROW, Key::SHIFT_TAB, Key::CTRL_P, Key::CTRL_B, 'k', 'h' => $this->highlightPrevious(count($this->options)),
-            Key::DOWN, Key::DOWN_ARROW, Key::RIGHT, Key::RIGHT_ARROW, Key::TAB, Key::CTRL_N, Key::CTRL_F, 'j', 'l' => $this->highlightNext(count($this->options)),
+            Key::UP, Key::UP_ARROW, Key::LEFT, Key::LEFT_ARROW, Key::SHIFT_TAB, Key::CTRL_P, Key::CTRL_B, 'k', 'h' => $this->highlightPrevious(count($this->options())),
+            Key::DOWN, Key::DOWN_ARROW, Key::RIGHT, Key::RIGHT_ARROW, Key::TAB, Key::CTRL_N, Key::CTRL_F, 'j', 'l' => $this->highlightNext(count($this->options())),
             Key::oneOf([Key::HOME, Key::CTRL_A], $key) => $this->highlight(0),
-            Key::oneOf([Key::END, Key::CTRL_E], $key) => $this->highlight(count($this->options) - 1),
+            Key::oneOf([Key::END, Key::CTRL_E], $key) => $this->highlight(count($this->options()) - 1),
             Key::SPACE => $this->toggleHighlighted(),
             Key::ENTER => $this->submit(),
             default => null,
         });
     }
 
+    /**
+     * Get the evaluated options, updating its cache when it's null.
+     *
+     * @return array<int|string, string>
+     */
+    public function options(): array
+    {
+        if ($this->evaluatedOptions !== null) {
+            return $this->evaluatedOptions;
+        }
+
+        $this->evaluatedOptions = match (true) {
+            is_callable($this->options) => ($ops = ($this->options)($this->value())) instanceof Collection ? $ops->all() : $ops,
+            default => $this->options,
+        };
+
+        if (empty($this->evaluatedOptions)) {
+            throw new NonInteractiveValidationException('All options are no longer available!');
+        }
+
+        $this->removeUnavailableValues();
+        $this->adjustHighlightedOption();
+
+        return $this->evaluatedOptions;
+    }
+
     /**
      * Get the selected values.
      *
@@ -71,18 +106,38 @@ public function value(): array
         return array_values($this->values);
     }
 
+    /**
+     * Remove values for unavailable options, after re-evaluation.
+     */
+    protected function removeUnavailableValues(): void
+    {
+        $hasLabels = array_keys($this->evaluatedOptions) !== range(0, count($this->evaluatedOptions) - 1);
+
+        foreach ($this->values as $key => $value) {
+            if ($hasLabels) {
+                if (!array_key_exists($value, $this->evaluatedOptions)) {
+                    unset($this->values[$key]);
+                }
+            } else {
+                if (!in_array($value, $this->evaluatedOptions)) {
+                    unset($this->values[$key]);
+                }
+            }
+        }
+    }
+
     /**
      * Get the selected labels.
      *
      * @return array<string>
      */
     public function labels(): array
     {
-        if (array_is_list($this->options)) {
+        if (array_is_list($this->options())) {
             return array_map(fn ($value) => (string) $value, $this->values);
         }
 
-        return array_values(array_intersect_key($this->options, array_flip($this->values)));
+        return array_values(array_intersect_key($this->options(), array_flip($this->values)));
     }
 
     /**
@@ -92,19 +147,19 @@ public function labels(): array
      */
     public function visible(): array
     {
-        return array_slice($this->options, $this->firstVisible, $this->scroll, preserve_keys: true);
+        return array_slice($this->options(), $this->firstVisible, $this->scroll, preserve_keys: true);
     }
 
     /**
      * Check whether the value is currently highlighted.
      */
     public function isHighlighted(string $value): bool
     {
-        if (array_is_list($this->options)) {
-            return $this->options[$this->highlighted] === $value;
+        if (array_is_list($this->options())) {
+            return $this->options()[$this->highlighted] === $value;
         }
 
-        return array_keys($this->options)[$this->highlighted] === $value;
+        return array_keys($this->options())[$this->highlighted] === $value;
     }
 
     /**
@@ -120,14 +175,30 @@ public function isSelected(string $value): bool
      */
     protected function toggleHighlighted(): void
     {
-        $value = array_is_list($this->options)
-            ? $this->options[$this->highlighted]
-            : array_keys($this->options)[$this->highlighted];
+        $value = array_is_list($this->options())
+            ? $this->options()[$this->highlighted]
+            : array_keys($this->options())[$this->highlighted];
 
         if (in_array($value, $this->values)) {
             $this->values = array_filter($this->values, fn ($v) => $v !== $value);
         } else {
             $this->values[] = $value;
         }
+
+        $this->state = 'toggle';
+    }
+
+    /**
+     * Adjust the highlighted entry, after re-evaluation.
+     */
+    protected function adjustHighlightedOption(): void
+    {
+        $totalOptions = count($this->evaluatedOptions);
+
+        if ($this->highlighted !== null && $this->highlighted >= $totalOptions) {
+            $this->highlighted = $totalOptions - 1;
+        }
+
+        $this->scrollToHighlighted($totalOptions);
     }
 }

src/Themes/Default/MultiSelectPromptRenderer.php

@@ -15,6 +15,10 @@ class MultiSelectPromptRenderer extends Renderer implements Scrolling
      */
     public function __invoke(MultiSelectPrompt $prompt): string
     {
+        if ($prompt->state === 'toggle' || $prompt->state === 'error') {
+            $prompt->evaluatedOptions = null;
+        }
+
         return match ($prompt->state) {
             'submit' => $this
                 ->box(
@@ -35,15 +39,15 @@ public function __invoke(MultiSelectPrompt $prompt): string
                     $this->truncate($prompt->label, $prompt->terminal()->cols() - 6),
                     $this->renderOptions($prompt),
                     color: 'yellow',
-                    info: count($prompt->options) > $prompt->scroll ? (count($prompt->value()).' selected') : '',
+                    info: count($prompt->options()) > $prompt->scroll ? (count($prompt->value()).' selected') : '',
                 )
                 ->warning($this->truncate($prompt->error, $prompt->terminal()->cols() - 5)),
 
             default => $this
                 ->box(
                     $this->cyan($this->truncate($prompt->label, $prompt->terminal()->cols() - 6)),
                     $this->renderOptions($prompt),
-                    info: count($prompt->options) > $prompt->scroll ? (count($prompt->value()).' selected') : '',
+                    info: count($prompt->options()) > $prompt->scroll ? (count($prompt->value()).' selected') : '',
                 )
                 ->when(
                     $prompt->hint,
@@ -62,12 +66,12 @@ protected function renderOptions(MultiSelectPrompt $prompt): string
             collect($prompt->visible())
                 ->map(fn ($label) => $this->truncate($label, $prompt->terminal()->cols() - 12))
                 ->map(function ($label, $key) use ($prompt) {
-                    $index = array_search($key, array_keys($prompt->options));
+                    $index = array_search($key, array_keys($prompt->options()));
                     $active = $index === $prompt->highlighted;
-                    if (array_is_list($prompt->options)) {
-                        $value = $prompt->options[$index];
+                    if (array_is_list($prompt->options())) {
+                        $value = $prompt->options()[$index];
                     } else {
-                        $value = array_keys($prompt->options)[$index];
+                        $value = array_keys($prompt->options())[$index];
                     }
                     $selected = in_array($value, $prompt->value());
 
@@ -90,8 +94,8 @@ protected function renderOptions(MultiSelectPrompt $prompt): string
                 ->values(),
             $prompt->firstVisible,
             $prompt->scroll,
-            count($prompt->options),
-            min($this->longest($prompt->options, padding: 6), $prompt->terminal()->cols() - 6),
+            count($prompt->options()),
+            min($this->longest($prompt->options(), padding: 6), $prompt->terminal()->cols() - 6),
             $prompt->state === 'cancel' ? 'dim' : 'cyan'
         )->implode(PHP_EOL);
     }

src/helpers.php

@@ -35,11 +35,11 @@ function select(string $label, array|Collection $options, int|string|null $defau
 /**
  * Prompt the user to select multiple options.
  *
- * @param  array<int|string, string>|Collection<int|string, string>  $options
+ * @param  array<int|string, string>|Collection<int|string, string>|Closure(array<int|string, string>): array<int|string, string>|Collection<int|string, string>  $options
  * @param  array<int|string>|Collection<int, int|string>  $default
  * @return array<int|string>
  */
-function multiselect(string $label, array|Collection $options, array|Collection $default = [], int $scroll = 5, bool|string $required = false, mixed $validate = null, string $hint = 'Use the space bar to select options.'): array
+function multiselect(string $label, array|Collection|Closure $options, array|Collection $default = [], int $scroll = 5, bool|string $required = false, mixed $validate = null, string $hint = 'Use the space bar to select options.'): array
 {
     return (new MultiSelectPrompt(...func_get_args()))->prompt();
 }

tests/Feature/MultiSelectPromptTest.php

@@ -104,6 +104,44 @@
     expect($result)->toBe(['Green']);
 });
 
+it('accepts closures', function () {
+    Prompt::fake([Key::ENTER]);
+
+    $result = multiselect(
+        label: 'What are your favorite colors?',
+        options: fn () => collect([
+            'Red',
+            'Green',
+            'Blue',
+        ]),
+        default: collect(['Green'])
+    );
+
+    expect($result)->toBe(['Green']);
+});
+
+it('can reactively change options', function () {
+    Prompt::fake([Key::DOWN, Key::SPACE, Key::DOWN, Key::SPACE, Key::UP, Key::SPACE, Key::SPACE, Key::ENTER]);
+
+    $result = multiselect(
+        label: "Pick up items (2 items slots available):",
+        options: fn($values) => collect([
+            'food' => 'Some food',
+            'map' => 'A map',
+            'jacket' => 'A life jacket',
+        ])->when(count($values) >= 2, fn ($collection) =>  $collection->only($values)),
+    );
+
+    expect($result)->toBe(['jacket', 'food']);
+});
+
+it('throws when options are empty', function () {
+    multiselect(
+        label: 'Hey, man! About the ahh... -just hold on... (keyboard typing)',
+        options: fn() => [],
+    );
+})->throws(NonInteractiveValidationException::class, 'All options are no longer available!');
+
 it('validates', function () {
     Prompt::fake([Key::ENTER, Key::SPACE, Key::ENTER]);