Localizing your Ext JS packages

Ext JS Packages

In our projects we use home brewed packages in our Ext JS applications. The advantage of packages (also your theme is a package) is that they can easily be used to share sources between different applications. That will increase the possibility of reusing of your own component development.

For example you have your own designed search toolbar at the top of your grids. Well such a toolbar would be a great candidate to put in your own package. That would make it easy to just add the package to your application requirements and start using the components without the hassle of copying and editing sources in your application source tree.

In this article I will show you how you can localize (i18n) a component in your package, the Sencha way. It is important to notice that we use Sencha CMD.

Difference between common shares and a package

There is more than one way to share code between applications. If you have a workspace with more than one application you can share code using a “common” folder. If you want to share code between different applications for different customers you can use the “common” folder as well, but it is more likely to use a package.

In a package we share components that we use in most of our applications. One of our packages we have called “Factory”. But you can give it almost any name you like. You can even have more packages.

“common” or package

To decide when to use the “common” folder for sharing or when to use a package is totally up to you. We use the “Factory” package only for those things that are completely independent to the specific functionality of an application. We want to keep the package lightweight and avoid having a lot of code in it that we will not use in our applications. In our package we have for example some singletons, some generic toolbars for a grid and form panel. We also have some overrides in our package.

A form field override with localization

I will show you how we have managed localization in our package by the use of a Ext.form.field.VTypes override.

As I said our package is called “Factory”. This has been created in our workspace “packages” folder with the command:

After doing this it will create in the “local” folder of your packages the folder “Factory”. Your package is ready to use.

I will skip some steps here and show you the structure of the package folder “Factory” that are relevant to this sample.


First thing to notice is that the “locale” folder is not coming when creating the package. So you have to create this folder manually. In this folder you put the folders with the languages you want to support like:

As you can see it follows the same structure as you would use for SASS or other overrides.

The source code in the “de” or German VTypes.js looks like this:

As you can see the “locale” itself is not in the path of the Ext.define. This is correct.

The original override in our package

In the “overrides” folder of our package we have:

In this VTypes.js we have the following code:

As you can see the Ext.define path has the “overrides” in it’s path. Most important thing to notice is that the override in the “locale” folder is not overriding “Factory.overrides.form.field.VTypes”, but “Ext.form.field.VTypes”. If you don’t do this, it will result in the error: “Cannot read property ‘$isClass’ of undefined“.


We need to make a small modification to the package.json of our “Factory” package.

We put the “${package.dir}/locale/${package.locale}” at the end of the “overrides” tag. I have taken this from the “ext-locale” package that comes with Ext JS. Don’t ask me why it works, but it works.

How to use the package in your application

To use the package in your application you have to modify the app.json file in your application root folder. You have to change the requires attribute the following way

or you modify the the requires according to the specific toolkit used

Next step with Sencha CMD

After modifying this I have done the following steps in Sencha CMD from the application folder:

  • sencha app refresh
  • sencha app watch (to continue development) or:
  • sencha app build (to build the application)

How it looks

Ext JS VTypes Localization

Reuse of the Ext JS package

To use your package in another application for a different purpose you can simply copy the “packages->local->Factory” folder and put in the packages->local folder of that other application/workspace. After modifying the requirements in the app.json and do a “sencha app refresh” it should also benefit the other application(s).

To keep any modifications to the package consistent however you should consider to work remote packages. How to do that I will show you in another article.


Official documentation on packages from Sencha

Johan van de Merwe
Dedicated to professional software development since 1985. Has worked since 1992 as IT manager in several international operating companies. Since 2007 CEO and Sencha Ext JS web application developer at Enovision GmbH.

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