Using the Ext JS Data Layer
The documentation for the ExtReact product diverges somewhat from the
documentation of other Sencha products. The sections below describe
documentation for all products except where indicated as unique to
ExtReact.
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.
ExtReact component classes list the configurable name prominently at the top of the API class doc followed by the fully-qualified class name.
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.
Public classes and class members are available for use by any other class or application code and may be relied upon as a stable and persistent within major product versions. Public classes and members may safely be extended via a subclass.
Protected class members are stable public members intended to be used by the
owning class or its subclasses. Protected members may safely be extended via a subclass.
Private classes and class members are used internally by the framework and are not intended to be used by application developers. Private classes and members may change or be omitted from the framework at any time without notice and should not be relied upon in application logic.
ExtReact component classes display
configuration options as props
ExtReact component classes do not list
properties as a dedicated member type, but rather as
read only props
static label next to the
method name. *See Static below.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).
Let's look at each part of the member row:
lookupComponent in this example)( item ) in this example)Ext.Component in this case). This may be omitted for methods that do not
return anything other than undefined or may display as multiple possible values
separated by a forward slash / signifying that what is returned may depend on the
results of the method call (i.e. a method may return a Component if a get method calls is
successful or false if unsuccessful which would be displayed as
Ext.Component/Boolean).PROTECTED in
this example - see the Flags section below)Ext.container.Container in this example). The source
class will be displayed as a blue link if the member originates from the current class
and gray if it is inherited from an ancestor or mixed-in class.view source in the example)item : Object in the example).undefined a "Returns" section
will note the type of class or object returned and a description (Ext.Component in the
example)Available since 3.4.0 - not pictured in
the example) just after the member descriptionDefaults to: false)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.
All ExtReact props are bindable
unless decorated as immutable
Immutable ExtReact props may not be use as a configurable prop when instantiating a component
classInstance.method1().method2().etc();false is returned from
an event handler- 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
- Indicates a class member of type config
Or in the case of an ExtReact component class this
indicates a member of type prop
- 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
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.
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.
ExtReact component classes do not hoist the getter /
setter methods into the prop. All methods will be described in the
Methods section
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.
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.
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:
Ext.button.Button class has an alternate class name of Ext.Button). Alternate class
names are commonly maintained for backward compatibility.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.
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:
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.
The data package is what loads and saves all of the data in your application. It consists of a multitude of classes, but there are three that are more important than all the others.
These classes are:
The above classes are used by almost every application. They are supported by a number of satellite classes.
The centerpiece of the data package is Ext.data.Model. A Model represents an entity in an
application. For example, an e-commerce app might have models for Users, Products and
Orders. At the simplest level, a Model defines a set of fields and related business logic.
Let's look at a few of the principal parts of Model:
It is usually best to define your models starting with a common base class. This base class allows you to easily configure certain aspects for all of your models in one place. It is also a good place to configure the schema. The schema is a manager for all of the models in your application. For now we'll focus on two of its most helpful configuration options:
Ext.define('MyApp.model.Base', {
extend: 'Ext.data.Model',
fields: [{
name: 'id',
type: 'int'
}],
schema: {
namespace: 'MyApp.model', // generate auto entityName
proxy: { // Ext.util.ObjectTemplate
type: 'ajax',
url: '{entityName}.json',
reader: {
type: 'json',
rootProperty: '{entityName:lowercase}'
}
}
}
});
The appropriate content for your model base class, especially its "fields", will likely differ between applications.
Proxies are used by Models and Stores to handle the loading and saving of Model data. There are two types of proxies: Client and Server.
Proxies can be defined directly on the schema of the Model's base class (as seen above).
Examples of client proxies include Memory and Local Storage, which uses the HTML5 localstorage feature. Although older browsers don't support these new HTML5 APIs, they're so useful that a lot of applications will benefit enormously from their presence.
Server proxies handle the marshaling of data to a remote server. Examples of this type of proxy include AJAX, JSONP and REST.
A schema is a collection of entities that have associations with one another. When a model specifies a "schema" config, that schema will be inherited by all derived models. In the above example, the schema has been configured with two values that establish the defaults for all models in that schema.
The first of these configs is the "namespace". By specifying this namespace all models gain a shortened name call an "entityName". This short name is primarily useful when defining associations between models which we will see later.
The example schema also defines a "proxy" config. This is an object template which is similar to textual templates based on Ext.XTemplate. The difference is that the object template produces objects when given its data. In this case, that data is used to automate the definition of the "proxy" config for all models that do not explicitly define a proxy.
This is very helpful since it's likely that every instance of model will need to load its data the same way with slightly different values. This avoids repetitive proxy definitions for each Model.
The User.json that we specify in the URL, url: '{entityName}.json', should return a
JSON string.
For this example we've used this:
{
"success": "true",
"user": [
{
"id": 1,
"name": "Philip J. Fry"
},
{
"id": 2,
"name": "Hubert Farnsworth"
},
{
"id": 3,
"name": "Turanga Leela"
},
{
"id": 4,
"name": "Amy Wong"
}
]
}
Models are typically used with a Store, which is basically a collection of records (instances of a Model-derived class). Creating a Store and loading its data is simple:
var store = new Ext.data.Store ({
model: 'MyApp.model.User'
});
store.load({
callback:function(){
var first_name = this.first().get('name');
console.log(first_name);
}
});
We are manually loading the store to receive a set of MyApp.model.User records. The
records are then logged when the store load's callback function is fired (upon completion).
Stores can also load data in-line. Internally, Store converts each of the objects we pass in as data into records of the appropriate Model type:
new Ext.data.Store({
model: 'MyApp.model.User',
data: [{
id: 1,
name: "Philip J. Fry"
},{
id: 2,
name: "Hubert Farnsworth"
},{
id: 3,
name: "Turanga Leela"
},{
id: 4,
name: "Amy Wong"
}]
});
Stores are able to perform sorting, filtering and grouping locally and remotely.
new Ext.data.Store({
model: 'MyApp.model.User',
sorters: ['name','id'],
filters: {
property: 'name',
value : 'Philip J. Fry'
}
});
In this store, the data will be sorted first by name and then id. The data will be filtered to only include users with the name 'Philip J. Fry'. It's easy to change the attributes for these items at any time via the Store's API.
When associations are defined, the act of loading a record can also load associated records in a single request. For example, consider a server response like this:
{
"success": true,
"user": [{
"id": 1,
"name": "Philip J. Fry",
"posts": [{
"title": "Post 1"
},{
"title": "Post 2"
},{
"title": "Post 3"
}]
}]
}
The framework can automatically parse out nested data in a single response such as the above. Instead of making a request for the User data and another for the Posts data, we can return all of the data in a single server response.
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