Configuration

Set shared defaults under Flash in your application's config/app.php or config/app_local.php:

'Flash' => [
    'key' => 'notifications',
    'limit' => 5,
    'params' => ['class' => 'notice'],
],

Merge this entry into the existing configuration array. Both the component and helper read it when they load, so one key and limit apply to both. See the complete example configuration.

For runtime setup before loading either class, the equivalent is:

Configure::write('Flash', [
    'key' => 'notifications',
    'limit' => 5,
]);

Import Cake\Core\Configure when using that form.

Explicit component or helper load options override shared values:

$this->loadComponent('Flash.Flash', ['limit' => 3]);

The helper still uses the shared limit of five unless you override it too. They share the transient stack, so a helper append trims existing controller entries to the helper's limit. Use matching settings unless you need different behavior.

Precedence is load options, shared Flash settings, then built-in defaults. An explicit array option such as params replaces the shared value for that option. Configure defaults before loading the classes; changing Configure afterwards does not update existing instances.

Component

Option	Default	Behavior
key	flash	Session/transient stack key; header output reads this key.
limit	10	Newest entries retained per key, separately in session and transient storage; use a positive integer.
params	[]	Default parameters supplied to elements.
clear	false	Replace existing session entries when true.
duplicate	true	Allow identical entries; false suppresses identical controller entries.
headerKey	X-Flash	AJAX response header; empty string disables it.
headerOnRedirect	false	Also inject the header before AJAX redirects.
noSessionOnAjax	true	Route normal AJAX message calls into transient storage.
ajaxDetectors	['ajax']	Request detectors used for AJAX handling and header output.

Typed calls select their corresponding element; message() defaults to info. Direct set(), message() and transientMessage() calls accept type, element, plugin, key, params and escape. Typed methods choose their type and element; they also accept plugin, key, params and escape. Session calls also accept clear and duplicate. Controller transient calls support duplicate.

A Throwable passed to the component becomes its message text, with its code stored in params.code unless you supplied that parameter yourself.

Helper

Option	Default	Behavior
key	flash	Stack used when render() has no explicit key.
limit	10	Newest transient entries retained per key when the helper appends; use a positive integer.
order	['error', 'warning', 'success', 'info']	Type order when rendering; other types follow.
params	[]	Default element parameters.

The helper's limit applies when it adds transient messages. It does not trim session messages supplied by the component. Render options can select types; direct message() also accepts element options as its third argument.