Is the automatic garbage collection of components a built-in feature of

Question

Is the automatic garbage collection of components a built-in feature of

Consider this scenario, where I have the following HTML document:

<html>
    <head>... including all the necessary js and css files here...</head>
    <body>
        <div class="placeholderForExtPanel"></div>
    </body>
</html>

At some point in my code, I instruct ExtJS to display a panel within the placeholder.

var container = Ext.select('.placeholderForExtPanel');
Ext.create('Ext.form.Panel', {
    title: 'My Panel'
});

Later on, another part of the code decides to remove the placeholder div from the DOM.

Ext.select('.placeholderForExtPanel').first().remove();

In this situation, what happens to the previously declared Panel? Do I need to manually destroy it, or does ExtJS recognize that its containing element has been removed from the DOM and automatically handle destroying the Panel? This applies specifically for ExtJS version 4.1.

javascript extjs garbage-collection

Answer 1

Answer №1

In ExtJS, components are not automatically destroyed when the containing element is removed. The element itself will be removed from the DOM, but the panel still maintains its reference to it. To remove the containing element and destroy the panel, you can use the following code:

Ext.select('.placeholderForExtPanel').first().remove();
console.log(Ext.getCmp('panel-id').getEl().dom.parentNode); // Assuming the panel's id is "panel-id"

Even though the element has been removed, it still exists and can be appended back to the DOM if needed:

document.body.appendChild(Ext.getCmp('panel-id').getEl().dom.parentNode);

(On a side note: because the panel keeps the reference to its containing element, the browser's garbage collector will not destroy it.)

In summary, in ExtJS, the component manages its associated DOM elements. When the component is destroyed, the corresponding DOM elements are also removed.

Additionally, any components that can contain other components, such as Ext.container.Container and its subclasses, will automatically destroy their child components when they are destroyed (assuming autoDestroy is enabled, which is the default behavior).

Therefore, if you want to automatically destroy all components rendered to a specific element, you can create that element as a container:

var container = Ext.create('Ext.container.Container', {
    cls: 'placeholderForExtPanel',
    renderTo: Ext.getBody(),
    items: [{
        xtype: 'panel',
        title: 'mypanel'
    }]
});

container.destroy(); // This will destroy both the container and the panel

Answer 2

In ExtJS, components are not automatically destroyed when the containing element is removed. The element itself will be removed from the DOM, but the panel still maintains its reference to it. To remove the containing element and destroy the panel, you can use the following code:

Ext.select('.placeholderForExtPanel').first().remove();
console.log(Ext.getCmp('panel-id').getEl().dom.parentNode); // Assuming the panel's id is "panel-id"

Even though the element has been removed, it still exists and can be appended back to the DOM if needed:

document.body.appendChild(Ext.getCmp('panel-id').getEl().dom.parentNode);

(On a side note: because the panel keeps the reference to its containing element, the browser's garbage collector will not destroy it.)

In summary, in ExtJS, the component manages its associated DOM elements. When the component is destroyed, the corresponding DOM elements are also removed.

Additionally, any components that can contain other components, such as Ext.container.Container and its subclasses, will automatically destroy their child components when they are destroyed (assuming autoDestroy is enabled, which is the default behavior).

Therefore, if you want to automatically destroy all components rendered to a specific element, you can create that element as a container:

var container = Ext.create('Ext.container.Container', {
    cls: 'placeholderForExtPanel',
    renderTo: Ext.getBody(),
    items: [{
        xtype: 'panel',
        title: 'mypanel'
    }]
});

container.destroy(); // This will destroy both the container and the panel

Is the automatic garbage collection of components a built-in feature of

Answer №1

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