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Terms, Icons, and Labels

Many classes have shortcut names used when creating (instantiating) a class with a configuration object. The shortcut name is referred to as an alias (or xtype if the class extends Ext.Component). The alias/xtype is listed next to the class name of applicable classes for quick reference.

Access Levels

Framework classes or their members may be specified as private or protected. Else, the class / member is public. Public, protected, and private are access descriptors used to convey how and when the class or class member should be used.

Member Types

Member Syntax

Below is an example class member that we can disect to show the syntax of a class member (the lookupComponent method as viewed from the Ext.button.Button class in this case).

lookupComponent ( item ) : Ext.Component

Called when a raw config object is added to this container either during initialization of the items config, or when new items are added), or {@link #insert inserted.

This method converts the passed object into an instanced child component.

This may be overridden in subclasses when special processing needs to be applied to child creation.


item :  Object

The config object being added.


The component to be added.

Let's look at each part of the member row:

Member Flags

The API documentation uses a number of flags to further commnicate the class member's function and intent. The label may be represented by a text label, an abbreviation, or an icon.

Class Icons

- Indicates a framework class

- A singleton framework class. *See the singleton flag for more information

- A component-type framework class (any class within the Ext JS framework that extends Ext.Component)

- Indicates that the class, member, or guide is new in the currently viewed version

Member Icons

- Indicates a class member of type config

- Indicates a class member of type property

- Indicates a class member of type method

- Indicates a class member of type event

- Indicates a class member of type theme variable

- Indicates a class member of type theme mixin

- Indicates that the class, member, or guide is new in the currently viewed version

Class Member Quick-Nav Menu

Just below the class name on an API doc page is a row of buttons corresponding to the types of members owned by the current class. Each button shows a count of members by type (this count is updated as filters are applied). Clicking the button will navigate you to that member section. Hovering over the member-type button will reveal a popup menu of all members of that type for quick navigation.

Getter and Setter Methods

Getting and setter methods that correlate to a class config option will show up in the methods section as well as in the configs section of both the API doc and the member-type menus just beneath the config they work with. The getter and setter method documentation will be found in the config row for easy reference.

History Bar

Your page history is kept in localstorage and displayed (using the available real estate) just below the top title bar. By default, the only search results shown are the pages matching the product / version you're currently viewing. You can expand what is displayed by clicking on the button on the right-hand side of the history bar and choosing the "All" radio option. This will show all recent pages in the history bar for all products / versions.

Within the history config menu you will also see a listing of your recent page visits. The results are filtered by the "Current Product / Version" and "All" radio options. Clicking on the button will clear the history bar as well as the history kept in local storage.

If "All" is selected in the history config menu the checkbox option for "Show product details in the history bar" will be enabled. When checked, the product/version for each historic page will show alongside the page name in the history bar. Hovering the cursor over the page names in the history bar will also show the product/version as a tooltip.

Search and Filters

Both API docs and guides can be searched for using the search field at the top of the page.

On API doc pages there is also a filter input field that filters the member rows using the filter string. In addition to filtering by string you can filter the class members by access level, inheritance, and read only. This is done using the checkboxes at the top of the page.

The checkbox at the bottom of the API class navigation tree filters the class list to include or exclude private classes.

Clicking on an empty search field will show your last 10 searches for quick navigation.

API Doc Class Metadata

Each API doc page (with the exception of Javascript primitives pages) has a menu view of metadata relating to that class. This metadata view will have one or more of the following:

Expanding and Collapsing Examples and Class Members

Runnable examples (Fiddles) are expanded on a page by default. You can collapse and expand example code blocks individually using the arrow on the top-left of the code block. You can also toggle the collapse state of all examples using the toggle button on the top-right of the page. The toggle-all state will be remembered between page loads.

Class members are collapsed on a page by default. You can expand and collapse members using the arrow icon on the left of the member row or globally using the expand / collapse all toggle button top-right.

Desktop -vs- Mobile View

Viewing the docs on narrower screens or browsers will result in a view optimized for a smaller form factor. The primary differences between the desktop and "mobile" view are:

Viewing the Class Source

The class source can be viewed by clicking on the class name at the top of an API doc page. The source for class members can be viewed by clicking on the "view source" link on the right-hand side of the member row.

Cmd 6.6.0


What's New in Sencha Cmd 6.6.0

Sencha Cmd 6.6.0 includes upgrade to support Ext JS 6.6

What's New in Sencha Cmd 6.5.3

Sencha Cmd 6.5.3 (and earlier version 6.5.2) includes an upgrade to the latest Google Closure Compiler and provides configuration options to manage the transpiler and tune polyfill settings.

Below are some common scenarios using ES6 and Sencha Cmd 6.5.3 :

Enable ES6

The most likely goal for developers is to take advantage of ES6 (and newer) versions of JavaScript. A second likely goal is for code to run on browsers that do not natively support ES6. To accomplish this, Sencha Cmd internally uses Google's Closure Compiler as a transpiler.

Enable Transpiler

By default Sencha Cmd enables all JavaScript language support as well as the transpiler so that the compiled application can run in an ES5 browser. Even though this is the default, the following settings explicitly enable this mode:

"language": {

    "js": {

        "output": "ES5"



The new "language" key holds settings for only the JavaScript language ("js") at this time. The js language settings contain "input" and "output" options. By default, "input" is configured to accept all recognized syntax. With the latest Closure Compiler, this includes ES8 keywords such as async and await.

Disable Transpiler

In many cases applications require modern browsers and would therefore benefit from disabling the transpiler. This is because the code produced by the transpiler is larger (by necessity) and must emulate modern language features. To disable the transpiler, we simply set the "output" and "input" js language levels such that the output level is greater than or equal to the input level:

"language": {

    "js": {

        "input": "ES6",

        "output": "ES6"



NOTE: In the current version of Closure Compiler, setting "output" to "ES6" or higher disables the transpiler regardless of "input" level, but this could change as Closure Compiler evolves. It is best to set both input and output levels as desired for future-proofing purposes.

Beyond ES6

Closure Compiler supports language features beyond ES6 such as async and await which are defined in ES8 (also known as ES2017). These constructs can be transpiled to ES5 so that your code will run on legacy browsers:

"language": {

    "js": {

        "input": "ES8",

        "output": "ES5"



Disable ES6 (no Transpiler)

For various reasons an application may decide not to enable ES6 support. In this case it is best to disable the ES6 parser to avoid accidental usage of ES6 syntax. This is done by setting the js language input level:

"language": {

    "js": {

        "input": "ES5"



With the above setting, ES6 syntax will be reported as syntax errors during a build. This is the mode in which Ext JS itself is compiled so as not to require the transpiler (or polyfills, see below) in all applications.


A "polyfill" is a piece of code that provides some missing piece of the standard library. ES6 and newer levels of JavaScript have added numerous new methods. So where a transpiler provides missing syntax support (such as arrow functions), polyfills provide missing methods.


This setting removes all polyfills. It is most appropriate (and is the default) for packages, but apps may also find this useful.

"compressor": {

    "polyfills": "none"


NOTE: Unlike the other settings described above, this setting is part of the "compressor" which is the internal component that includes the polyfills.


In addition to newly standard JavaScript API's, Closure Compiler uses special internal functions in its transpiler. While these pieces are not technically polyfills, they are injected in the same way. To include only these pieces and none of the JavaScript API's, do the following:

"compressor": {

    "polyfills": "syntax"


This setting is appropriate for transpiled applications that want to save some space by not including implementations of new ES6+ methods. For example, an implementation of Promise will be included, however, Ext JS already has its own.

Generally this will produce the smallest amount of extra code to support ES6+ syntax.


Closure Compiler has logic to determine what polyfills are needed and include only those pieces. To enable this mode, use:

"compressor": {

    "polyfills": "auto"


Typically this will include a bit more code than the "syntax" level.


While the "auto" polyfill mode is tempting, JavaScript's dynamic nature can theoretically result in uses of ES6 methods escaping detection. To be as safe as possible, all polyfills can be included like so:

"compressor": {

    "polyfills": "all"


While this includes the more code compared to "auto" and "syntax", it is the safest mode for applications that make heavy use of new ES6 methods. This is also a good way to go when dynamically loading packages that may need polyfills not required for the application.

What's New in Sencha Cmd 6.5.1

Sencha Cmd 6.5.1 helps you to create optimal builds for large web applications. It includes the following key features:

Minimum Build for Dynamically Loaded Packages

In Ext JS 6.5.0, the build output for applications that used the new dynamic package loader included all framework classes. That was because the dynamically loaded packages were built separately and their framework dependencies were not known to the application.

With Ext JS 6.5.1, the class requirements of dynamic packages can be passed to the application build and allow it to include only those classes needed, as shown below:

"output": {
    "js": {
        "filter": "minimum"   

The alternate filter options are “all” which includes all code from required packages, and “used” (the default behavior in 6.5.0) which includes all code from packages that are required by the app and any package that it uses.

Manually Exclude Classes from Build

You can now manually exclude class names from the build. This is helpful for removing code that is detected by the Sencha Cmd auto dependency scanner, but is not actually used by your application. For example:

"js": {
    "exclude": [

What's New in Sencha Cmd 6.5


Sencha Cmd 6.5 has several major and minor features and enhancements that will help streamline your development process and take advantage of the latest web technologies and get the most out of Ext JS 6.5.

ECMAScript 2015 (or ES6)

With Sencha Cmd 6.5 you can write code using arrow functions, the let keyword, object de-structuring and pretty much all the cool new features in ES6. Sencha Cmd will compile your code to run everywhere. This translation is called a "transpiler" and under the covers, Sencha Cmd uses Google's Closure Compiler to transpile your code.

Cmd also leverages all the poly-fills provided by Closure so you can also use those fancy new Array methods and not worry which browsers support them.

There are cases where you won't need all that transpiling. Maybe you’re targeting Electron or you only support modern browsers that have all these features. You can disable the transpiler and still use the Sencha Cmd code compressor against your native ES6 code. Just a tweak to the app.json file and say goodbye to the transpiler and its polyfills:

"output": {
    "js": {
        "version": "ES6"

Dynamic Package Loading

Sencha Cmd has supported the concept of packages for several years and large-scale applications often leverage packages to encapsulate classes, styling, and resources. Sencha Cmd then builds all of these pieces into your application. Now, you can use these packages in a whole new way – dynamically.

If you’re using packages today, you would see them in your app.json "requires" array:

requires: [

To switch to dynamic loading, simply move some or all of these into the "uses" array and add a new package to "requires":

requires: [
uses: [

After these changes, when Sencha Cmd builds your application, it will generate separate bundles for the application and each of the used packages. When your application loads, it will contain only its code and the code from its required packages, but not the used packages. Instead the JavaScript, CSS, and resources for these used packages will be in the application's build folder just like images or other assets.

The Ext.Package.load() method then makes it trivial to load packages when you’re ready for them. The package loader handles the package's JavaScript and CSS assets as well as recursively loading any packages that it may require.

If you’re using Ext JS routes, you might do something like this to load a package:

routes: {
    ':type': {
        before: 'loadPackage',
        action: 'showView'

loadPackage: function (type, action) {
    var view = this.getView(),
        pkg = this.getPackageForType(type);

    if (!pkg || Ext.Package.isLoaded(pkg)) {
    else {
            message: 'Loading Package...'

        Ext.Package.load(pkg).then(function () {


Using dynamic package loading can be a real time-saver for your users. No longer will they have to wait for every byte of your application to load when in reality they only needed about 20% of it. It can also save time for developers because Sencha Cmd no longer has to load all their code to make a "dev" build or watch all their code at the same time.

There are a number of new command line switches to "app build" and "app watch" to give you control over which external packages (if any) to build or watch. These allow you to slash your build times by limiting builds to only the package(s) on which you’re currently working.

See It In Action

To get you started, we’ve written a demo application that uses a handful of packages in some real-world scenarios. Check out the GitHub repo.

Progressive Web Apps

Progressive Web Apps (PWAs) provide a near-native app experience using modern web technologies. With a PWA, you can display a banner that invites Android users to install your app on their home screen. Through the magic of the service worker and its caching (currently supported in Chrome and Firefox), your app can even run offline.

Sencha Cmd streamlines the build process by providing a pre-built service worker (based on Google's ). The service worker can be configured in app.json, and its cache manifest can be augmented by Sencha Cmd using @sw-cache comments in your source code. These comments tell Cmd that you need to cache particular resources and can also configure how each asset should be managed.

PWA Example

We've pulled together a progressive web application example to show you how it all works. Check out the GitHub repo and follow the README instructions to get started. The GitHub repo contains both the Ext JS App and the Node.js based back-end server.

Project Structure

With Sencha Cmd 6.5, generated applications no longer contain the build scripts used by the "sencha app build" command. Instead of putting these in a local .sencha folder, these scripts are now loaded from the Sencha Cmd install directory.

The "sass" directory is also no longer generated for applications. Instead you can put your *.scss files in the same directory as the JavaScript files. In other words, for the Foo view, you would potentially have all these files:


It is recommended to put general or global styling in app/Application.scss or in files imported from there.

Framework Management

To streamline setting up new projects, you can take advantage of the new "sencha app init" and "sencha app install" commands and their "workspace" counterparts "sencha workspace init" and "sencha workspace install" if you have multiple applications.

All of these commands accept a path to where you have extracted Ext JS. If you download and extract all Sencha SDK's into a single folder, you can streamline these commands like so:

$ sencha config --prop sencha.sdk.path=~/sencha-sdks --save

On Windows the "~" part of the path will be replaced by something like "C:\Users\Me\".

Now that "sencha-sdks" has all the SDK zips you have downloaded and extracted, and you have saved that path using "sencha config --save" you won't need to pass --frameworks to any of the init or install commands.

Known Issues

Some users may have difficulty building their native Cordova applications after upgrading to Cmd 6.5.0. If you receive any errors related to Cordova platform configs, please manually create a file named if none exists. Then place the following code within the file and try building again:


Note: should placed in the root directory of your project.

Cmd 6.6.0