Ext JS 4.2.1 Sencha Docs

Creating Sencha Cmd Packages

Sencha Cmd includes the Sencha Package Manager. Packages have many uses even if you do not intend to distribute the packages you create. This guide covers to process of creating your own packages as well as distributing them. For information on using packages please refer to Sencha Cmd Packages.

Generating Packages

Before we can generate a new package, we must first create a home for it: a Workspace. For this example we will use Ext JS for this package, so we start with this command:

sencha -sdk /path/to/ext-n.n.n generate workspace /path/to/workspace

Now we navigate to the new workspace and generate the package:

cd /path/to/workspace
sencha -sdk ext generate package foo

Anatomy of a Package

The above steps produce a starter package that contains many commonly used pieces. You can delete many of these but it is important to keep the ".sencha" folder intact.

The structure of a package generated by sencha generate package is as follows:

    foo/                        # Top-level folder for the package
                sencha.cfg      # Sencha Cmd configuration for this package
                build-impl.xml  # Generated build script for package
                plugin.xml      # Sencha Cmd plugin for this package
                codegen.json    # Data to support 3-way merge in code generator
        docs/                   # Documentation for the package
            screenshots/        # Screen shots for Sencha Market
        licenses/               # License agreement
        overrides/              # Folder for automatically activated overrides
        resources/              # Static resources (typically has images folder)
        sass/                   # Container for Sass code
            etc/                # General, non-component oriented Sass
            src/                # Sass rules and mixins named by component
            var/                # Sass variables named by component
        src/                    # Folder for normal JavaScript code
        build.xml               # Build script (called by `sencha package build`)
        package.json            # Package descriptor
        Readme.md               # High-level information about this package

While the above is quite extensive, the only parts that are required to be a package are these: "package.json" and ".sencha/package/sencha.cfg".

The "package.json" file contains a description of the package. An example of this from the "ext-theme-neptune" package:

    "name": "ext-theme-neptune",
    "type": "theme",
    "creator": "Sencha",
    "summary": "Ext JS Neptune Theme",
    "detailedDescription": "The Neptune Theme provides a clean, modern style for Ext JS",
    "version": "n.n.n",
    "compatVersion": "n.n.n",
    "format": "1",
    "extend": "ext-theme-neutral"

The creator property is something you need to set as a package author. There is no verification of this text, but it must match the name you assign to your local package repository discussed later.

The ".sencha/package/sencha.cfg" file is primarily important to the developer of the package as it is used by Sencha Cmd during sencha package build. It is also used by by user applications during their sencha app build process.

Integrating Packages in Application Builds

The purpose of most packages is to (eventually) become integrated in an application. To accomplish this, Sencha Cmd incorporates the various pieces of each required package in to an application during the sencha app build process.

Precisely how this takes place depends on the type of the package.

Package Type

Different types of packages play different roles. Sencha Cmd understands the following types of packages:

  • code - An arbitrary package of code for use by applications or other packages. These packages are general purpose and are included when there is a require statement that selects them.
  • theme - A package to be used as an application's theme. Themes are special in that only one package of type theme is allowed to be "active" in a build. This theme is selected by the app.theme property and it causes all other theme packages that may be in a require to be filtered out. Themes can also use extend to inherit Sass and resources from another theme package.
  • locale - A package containing localization strings or locale-specific code. These packages have a similar selection method to theme packages. Packages of this type add a property to their "package.json" called "locale". This should be set to the name of the locale to which this package applies (e.g., "he" for Hebrew). The app.locale property, if set, causes any package of this type with a different value in its locale to be filtered out. This means you can have many different locale packages with the same locale value and they will all be included

Source Code

The "src" folder is the place for classes such as custom components or other useful code. This code is automatically included in the classpath for applications or other packages to require and use.

This is where you would likely put most of your JavaScript code. Classes placed in this folder should follow the Compiler-Friendly Code Guidelines.


The "sass" folder contains three sub-folders designed to handle different aspects of Sass compilation.

  • "sass/etc" - Code that does not relate directly to JavaScript classes
  • "sass/var" - Variable definitions (mirroring JavaScript class hierarchy)
  • "sass/src" - Mixins and rules (mirroring JavaScript class hierarchy)

The folders and files in "sass/var" and "sass/ssrc" are organized such that they are mirror images of the JavaScript classes to which they apply. This correspondence allows Sencha Cmd to include the files needed by the application. Files in these folders that do not conform to this will never be included since the process proceeds by mapping the JavaScript class hierarchy to the file system and not be scanning these folders.

The package.sass.namespace (in ".sencha/package/sencha.cfg") determines the top-level namespace to which your styling applies. This defaults to Ext for packages. You will most likely need to change this in order to associate your Sass with your classes inside your package's namespace.


The "resources" folder is where you place static resources needed by the package. When applications consume the package, they will copy these resources into a sub-folder of their own "resources" folder named by the package name. In this case, "resources/foo". The relative paths used by Sass will be automatically corrected if you use the provided theme-background-image method.


The "overrides" folder is specifically intended for your package to provide mandatory overrides, hence its name. This mechanism should be used cautiously because all code you place in this folder will be automatically required in to any application that uses this package.

The Ext JS Neptune Theme uses this mechanism to change certain default config properties on various components. Locale packages use this to inject their own text on to the prototypes of various components or to provide locale-specific logic for things such as date formatting.

Package Versions

Packages have a version property that describes its current version number. In addition the current version (in the version property), packages can also indicate the degree to which they are backward compatible using the compatVersion property.

These versions are used when resolving package requirements. Each release of a package should have an updated version number. The meaning assigned to version numbers by Sencha may help you:


x = Major release number (large, impacting changes and features)
y = Minor release number (new functionality but few if any breaking changes)
z = Patch release number (bug fix / maintenance release - goal of 100% compatible)
b = Build number (assigned by build system)

The version property is typically the easiest to maintain. The compatVersion, however, is an intentional statement about the degree to which users should be able to transparently upgrade and not require code changes.

Package Requirements

Packages can require other packages in the same way that applications can require packages. To do this, you add to the requires array:

    "name": "bar",
    "type": "code",
    "creator": "anonymous",
    "summary": "Short summary",
    "detailedDescription": "Long description of package",
    "version": "1.0.0",
    "compatVersion": "1.0.0",
    "format": "1",
    "local": true,
    "requires": [

NOTE: When using version restrictions as a package author, it is important to consider that an application and all of the required packages will have to agree on a common version. If you are too restrictive, this process can fail to find a mutually agreeable version for all of the required packages.

Package Inheritance

The notion of inheritance for packages is intended exclusively for Themes. These are most important ways in which the inherited package contents are rolled into the derived package:

  • The "resources" folders of inherited packages is copied in to the "resources" folder in the "build" output folder.
  • The overrides of base packages are automatically included in the build output of the derived package.

Building The Package

To publish the package, you will need to build it using:

sencha package build

This produces a "build" folder inside the package. This is needed by applications when they are running in "dev mode" (without being compiled). It also produces "foo.pkg" file in your workspace's "build" folder. This file is not placed in the package's "build" folder because:

  • It is a ZIP file of your package folder.
  • It is not needed by users of the package.

The "foo.pkg" file is used to add the package to your local repository. See below.

NOTE: In older versions of Sencha Cmd, sencha package build may fail if you have Sass that depends on the theme. To workaround this limitation, you can set the skip.sass and skip.slice properties in ".sencha/package/sencha.cfg". The package will be usable in an application because the theme will be included in sencha app build.

Local Repository

The local repository was introduced in Sencha Cmd Packages, but there is more to know about it when you want distribute the packages you have created.


The local repository generated by Sencha Cmd looks like this:

        sencha.cfg                  # Sencha Cmd configuration for the repo
        plugin.xml                  # Plugin for repository hooks
        private-key.json            # Private key for repo

        remotes/                    # Storage for remote repositories
            remoteName/             # Name given at `sencha repo add`
                catalog.json        # Last catalog from this remote

        trust/                      # Unused in this release
            <somename>.cert.json    # Copy of `cert.json` (a public key)

    catalog.json                    # Catalog of all packages in this repo
    cert.json                       # Public key for this repo

        catalog.json                # Catalog for all versions of Foo package
        cert.json                   # Public key for creator of Foo package

        1.0/                        # Folder containing version 1.0
            Foo.pkg                 # Zip file of package
            package.json            # Extracted package descriptor


Author Identity

When Sencha Cmd generates the default local repository, it does not require you to provide any kind of identity. This is fine for its role as a cache, but as a package author you need to put your name on the packages you publish. Before you can publish packages you need to initialize your local repository with an identity:

sencha package repo init -name "My Company" -email "support@mycompany.com"

After this step, your name and email address will be recorded in the local repository along with a new public/private key pair.

NOTE: The name argument must match the value of the creator property you set in the "package.json".

Public/Private Keys

Your name, email and public key are stored in the "pkgs/cert.json" file. This file will be automatically added to the packages you create to identify you as the package author.

Obviously given its name, your private key is not intended to be shared with others. It is stored in your local repository in ".sencha/repo/private-key.json".

You might want to back up these two files as they will serve more important roles in future releases.


The "pkgs" folder is where all the packages are stored. These may be packages you have created or packages that you have downloaded.

When you add package ".pkg" files, these will be copied in to the "pkgs" folder tree.

Repository Hooks

The ".sencha/repo/plugin.xml" file is an Ant script that you can use to provide "hooks" into repository actions such as sencha package add. For more details on this, refer to the comments in the generated file.

Since: Sencha Cmd vn.n.n

Adding Packages

Once you have the ".pkg" file from the build, and assuming that the name you have set as your identity on your local repository matches the creator property defined in your "package.json", you can run this command:

sencha package add foo.pkg

Sencha Cmd will produce a hash of the ".pkg" file using your private key and add it to the ".pkg" file you specify and it will then copy that file to the local repository.

Now that the package reside in the repository, other developers can require it if they have added your repository as a remote.

The process to request that Sencha add your ".pkg" to the Sencha Package Repository is still being finalized, but you can check Sencha Market for updates on this.

Hosting A Package Repository

The structure of the "pkgs" folder is the structure expected for a remote repository. All that is required for others to require the packages you create is for them to add a remote repository:

sencha package repo add my-company http://my.company.com/packages

That is, assuming you have hosted your "pkgs" folder content at the above HTTP URL. There is nothing required of that hosting beyond HTTP GET access so a static file server or CDN will work.