FieldtypeModule class

// When instantiateModule=false (default): value is a class name string
$className = $page->module_field;  // e.g. 'InputfieldText' or null if not set
if($className) {
    $module = $modules->get($className);
}

// When instantiateModule=true: value is a live Module instance
$module = $page->module_field;
if($module instanceof Module) {
    // use the module directly
}

// Set by class name (works regardless of instantiateModule setting)
$page->module_field = 'InputfieldText';
$page->save('module_field');

// Set by Module instance (also works regardless of setting)
$page->module_field = $modules->get('InputfieldText');
$page->save('module_field');

// Clear the value
$page->module_field = null;
$page->save('module_field');

// Match by module class name
$pages->find('module_field=InputfieldText');
$pages->find('module_field!=InputfieldText');

Supports = and != operators only. Both module class names and numeric module IDs are accepted as selector values.

• This fieldtype is only visible in advanced mode in the field editor (isAdvanced() === true).
• moduleTypes: array of type prefixes or class names to filter which modules are selectable.
• matchType: 'prefix' matches modules by name prefix (faster); 'verbose' matches by class inheritance (more flexible).
• instantiateModule: when true, the field value is a live Module instance; when false (default), it is the module class name string.
• blankType: controls what an empty/unset field returns — null (default), 0, false, or a ModulePlaceholder instance.
• Database column: data INT NOT NULL (stores the module's numeric ID).
• Compatible fieldtypes: FieldtypeModule only.