The issue you’re encountering happens because InvokeCommand
in Drupal is intended to call a jQuery function on an element or selector. In your case, you’re trying to call a custom event (sendMessage
), which isn’t a jQuery function but a custom event handler.
The InvokeCommand
method expects to call a function like .hide()
, .show()
, .addClass()
, etc., but you’re passing an event (sendMessage
) which causes the error Ajax: TypeError: $element[response.method] is not a function
.
Solution:
To trigger a custom event using Drupal’s AJAX system, you should use PrependCommand
, AppendCommand
, or a CustomCommand
to call your JavaScript function or trigger an event instead of InvokeCommand
.
Here’s how you can fix this issue:
1. Use PrependCommand
to Trigger Custom JS:
Update your PHP code to use PrependCommand
instead of InvokeCommand
. This will allow you to prepend a custom JavaScript call into your HTML and execute it.
php
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use Drupal\Core\Ajax\PrependCommand;
use Drupal\Core\Ajax\AjaxResponse;
public function ajaxCallback(array &$form, FormStateInterface $form_state)
{
$response = new AjaxResponse();
// Trigger a custom event with PrependCommand.
$response->addCommand(new PrependCommand('body', '<script>jQuery(document).trigger("sendMessage", ["test"]);</script>'));
return $response;
}
2. Update Your JavaScript:
In your JavaScript code, make sure the sendMessage
event is being handled properly.
javascript
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(function ($, Drupal, drupalSettings) {
$(document).ready(function() {
// Listen for the custom 'sendMessage' event.
$(document).on('sendMessage', function(event, msg) {
alert('MY_EVENT: ' + msg);
});
});
})(jQuery, Drupal, drupalSettings);
How It Works:
- In the PHP code,
PrependCommand
is used to inject a script that triggers the sendMessage
event on the document
object.
- The JavaScript code listens for the
sendMessage
event and triggers the alert
with the message passed from the server.
Why InvokeCommand
Didn’t Work:
InvokeCommand
is designed to call a jQuery function on a specific element or selector. Since sendMessage
is a custom event and not a jQuery function, this caused the error. By using PrependCommand
or even CustomCommand
, you can execute arbitrary JavaScript that fits your need.
CustomCommand (Optional Alternative):
If you want more flexibility, you could define a custom command in Drupal and use it. But the above solution with PrependCommand
should solve your issue without adding complexity.