Extension code being called multiple times during boot

axdr

I've created an extension using Quick start http://flarum.org/docs/extend/start/

When I am adding items to HeaderSecondary it happens 3 times and 3 sets of items are created during the boot. Last instance is on the page.

main.js:

import { extend } from 'flarum/extend';
import HeaderSecondary from 'flarum/components/HeaderSecondary';

window.a_iniTimes = 0;
window.a_instances = [];

app.initializers.add('axdr-test', () => {
  extend(HeaderSecondary.prototype, 'items', function(items) {
    a_iniTimes++;
    items.add('test', <span>{ 'Test ' + a_iniTimes }</span>);
    a_instances.push(items); 
  });
});

after loading:

a_iniTimes:  3
a_instances: {ItemList {..}, ItemList {..}, ItemList {..}}

bootstap.php:

<?php

use Flarum\Event\ConfigureClientView;
use Illuminate\Contracts\Events\Dispatcher;

return function (Dispatcher $events) {
    $events->listen(ConfigureClientView::class, function (ConfigureClientView $event) {
        if ($event->isForum()) {
            $event->addAssets(__DIR__.'/js/forum/dist/extension.js');
            $event->addBootstrapper('axdr/test/main');
        }
    });
};

composer.json:

{
    "name": "axdr/test",
    "type": "flarum-extension",
    "description": "Test extension bug",
    "license": "MIT",
    "extra": {
        "flarum-extension": {
            "title": "axdr Test"
        }
    }
}

gulp.js:

var gulp = require('flarum-gulp');

gulp({
  modules: {
    'axdr/test': 'src/**/*.js'
  }
});

What will you say?

Toby

Hmm, interesting. What is the output of this database query:

SELECT `value` FROM `settings` WHERE `key` = 'extensions_enabled'

axdr

Toby SELECT value FROM settings WHERE key = 'extensions_enabled'

["flarum-approval", "flarum-bbcode", "flarum-emoji", "flarum-english", "flarum-flags", "flarum-likes",
"flarum-lock", "flarum-markdown", "flarum-mentions", "flarum-sticky", "flarum-subscriptions",
"flarum-suspend", "flarum-tags"]

Toby

OK. My thought there was that maybe the extensions had somehow been enabled multiple times, causing it to add the bootstrapper and run the code multiple times as well. But that doesn't seem to be the case.

When you view the source of the forum index, do you see this multiple times, or just once?

System.get('axdr/test/main');

axdr

Toby Have you done something?
It's allright now.
a_iniTimes = 1

System.get('axdr/test/main');

returns empty []{} (don't know what it is)

luceos

axdr what Toby would like to know is how often that piece of code shows up in your source. It's probably in the non-localized js file.

axdr

luceos Toby

What do you mean? -- "view the source of the forum index"
When I visit the index page of forum I see 1 label "Test 5"
Now when I view the index page a_iniTimes is 5
a_instance[0] == a_instance[4] - false
System.get('axdr/test/main') from console returns '[]{ }'
What is 'non-localized js file'?
I'll try to reboot server....

Berlyn

axdr What they are asking is when you view the source of the forum index page, do a CTRL+F and look for any lines of code that have:

System.get('axdr/test/main');

And see if it occurs more than once.

axdr

Berlyn Sorry.
I undestood.
In source of the forum index is only one System.get('axdr/test/main').

I noticed one thing. If I navigate from a post to the index and to a post "Test ?" increments (1, 3, 5, ...).
After refreshing again "Test 1".

I inserted

alert("ini = " + a_iniTimes);

When I press post-link 'alert' appears 3 times.
When I go to index - only 1 time.
Variable 'window' doesn't reinitialize.

When I click to Reply 'alert' appears many times.
When I click to 'Write' it also appears.
When I press Tab to move between controls 'alert' appeares and I cannot write anything.

Toby

Ah, of course. My apologies for the confusion.

This is more or less the expected behaviour.

Read about how Mithril.js, the JavaScript framework that Flarum uses, works. Every time the page is redrawn, the whole virtual DOM is reconstructed from scratch. This includes calling the HeaderSecondary component's items method to rebuild the list of header items.

In some instances we might be redrawing more than once needlessly – like you say, 3 times during the boot. These extra redraws could potentially be optimized away to increase performance in the future (where it doesn't increase code complexity too much). But it's not a problem in terms of how your extension works.