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.
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.
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.
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
- 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.
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.
Ext.util.Scheduler
Ext.data.Session
Ext.app.bind.RootStub
Ext.app.bind.LinkStub
Ext.app.bind.Multi
Ext.app.bind.Formula
Ext.app.bind.TemplateBinding
Ext.data.ChainedStore
This class manages arbitrary data and its relationship to data models. Instances of
ViewModel
are associated with some Component
and then used by their child items
for the purposes of Data Binding.
The most commonly used aspect of a ViewModel
is the bind
method. This method takes
a "bind descriptor" (see below) and a callback to call when the data indicated by the
bind descriptor either becomes available or changes.
The bind
method, based on the bind descriptor given, will return different types of
"binding" objects. These objects maintain the connection between the requested data and
the callback. Bindings ultimately derive from Ext.app.bind.BaseBinding
which provides several methods to help manage the binding.
Perhaps the most important method is destroy
. When the binding is no longer needed
it is important to remember to destroy
it. Leaking bindings can cause performance
problems or worse when callbacks are called at unexpected times.
The types of bindings produced by bind
are:
A "bind descriptor" is a value (a String, an Object or an array of these) that describe
the desired data. Any piece of data in the ViewModel
can be described by a bind
descriptor.
The simplest and most common form of bind descriptors are strings that look like an
Ext.Template
containing text and tokens surrounded by "{}" with dot notation inside
to traverse objects and their properties.
For example:
'Hello {user.name}!'
'You have selected "{selectedItem.text}".'
'{!isDisabled}'
'{a > b ? "Bigger" : "Smaller"}'
'{user.groups}'
All except the last are Ext.app.bind.TemplateBinding
which use the familiar Ext.Template
syntax with some slight differences. For more on
templates see Ext.app.bind.Template
.
The last descriptor is called a "direct bind descriptor". This special form of
bind maps one-to-one to some piece of data in the ViewModel
and is managed by the
Ext.app.bind.Binding
class.
A direct bind descriptor may be able to write back a value to the ViewModel
as well
as retrieve one. When this is the case, they are said to be "two-way". For example:
var binding = viewModel.bind('{s}', function(s) { console.log('s=' + s); });
binding.setValue('abc');
Direct use of ViewModel
in this way is not commonly needed because Ext.Component
automates this process. For example, a textfield
component understands when it is
given a "two-way" binding and automatically synchronizes its value bidirectionally using
the above technique. For example:
Ext.widget({
items: [{
xtype: 'textfield',
bind: '{s}' // a two-way / direct bind descriptor
}]
});
With two exceptions (see below) an Object is interpreted as a "shape" to produce by treating each of its properties as individual bind descriptors. An object of the same shape is passed as the value of the bind except that each property is populated with the appropriate value. Of course, this definition is recursive, so these properties may also be objects.
For example:
viewModel.bind({
x: '{x}',
foo: {
bar: 'Hello {foo.bar}'
}
},
function (obj) {
// obj = {
// x: 42,
// foo: {
// bar: 'Hello foobar'
// }
// }
});
Arrays are handled in the same way. Each element of the array is considered a bind descriptor (recursively) and the value produced for the binding is an array with each element set to the bound property.
One exception to the "object is a multi-bind" rule is when that object contains a
bindTo
property. When an object contains a bindTo
property the object is understood
to contain bind options and the value of bindTo
is considered the actual bind
descriptor.
For example:
viewModel.bind({
bindTo: '{x}',
single: true
},
function (x) {
console.log('x: ' + x); // only called once
});
The available bind options depend on the type of binding, but since all bindings
derive from Ext.app.bind.BaseBinding
its options are always applicable.
For a list of the other types of bindings, see above.
When a direct bind is made and the bound property is an object, by default the binding callback is only called when that reference changes. This is the most efficient way to understand a bind of this type, but sometimes you may need to be notified if any of the properties of that object change.
To do this, we create a "deep bind":
viewModel.bind({
bindTo: '{someObject}',
deep: true
},
function (someObject) {
// called when reference changes or *any* property changes
});
The ViewModel
has a scheduler attached that is used to coordinate the firing of bindings.
It serves 2 main purposes:
Example:
viewModel.bind('{val}', function(v) {
console.log(v);
});
viewModel.set('val', 1);
viewModel.set('val', 2);
viewModel.set('val', 3);
viewModel.set('val', 4);
The ViewModel
can be forced to process by calling notify
, which will force the
scheduler to run immediately in the current state.
viewModel.bind('{val}', function(v) {
console.log(v);
});
viewModel.set('val', 1);
viewModel.notify();
viewModel.set('val', 2);
viewModel.notify();
viewModel.set('val', 3);
viewModel.notify();
viewModel.set('val', 4);
viewModel.notify();
A Ext.data.Session manages model instances and their associations.
The ViewModel
may be used with or without a Session
. When a Session
is attached, the
ViewModel
will always consult the Session
to ask about records and stores. The Session
ensures that only a single instance of each model Type/Id combination is created. This is
important when tracking changes in models so that we always have the same reference.
A ViewModel
provides functionality to easily consume the built in data package types
Ext.data.Model and Ext.data.Store, as well as their associations.
A model can be described declaratively using links. In the example code below,
We ask the ViewModel
to construct a record of type User
with id: 17
. The model will be loaded
from the server and the bindings will trigger once the load has completed. Similarly, we could also
attach a model instance to the ViewModel
data directly.
Ext.define('MyApp.model.User', {
extend: 'Ext.data.Model',
fields: ['name']
});
var rec = new MyApp.model.User({
id: 12,
name: 'Foo'
});
var viewModel = new Ext.app.ViewModel({
links: {
theUser: {
type: 'User',
id: 17
}
},
data: {
otherUser: rec
}
});
viewModel.bind('{theUser.name}', function(v) {
console.log(v);
});
viewModel.bind('{otherUser.name}', function(v) {
console.log(v);
});
Bindings have the functionality to inspect the parent values and resolve the underlying value dynamically. This behavior allows model fields to be interrogated as part of a binding.
Ext.define('MyApp.model.User', {
extend: 'Ext.data.Model',
fields: ['name', 'age']
});
var viewModel = new Ext.app.ViewModel({
links: {
theUser: {
type: 'User',
id: 22
}
}
});
// Server responds with:
{
"id": 22,
"name": "Foo",
"age": 100
}
viewModel.bind('Hello {name}, you are {age} years old', function(v) {
console.log(v);
});
It is possible to bind to the certain state properties of a record. The available options are:
Example usage:
Ext.define('MyApp.model.User', {
extend: 'Ext.data.Model',
fields: [{
name: 'name',
validators: 'presence'
}, {
name: 'age',
validators: {
type: 'range',
min: 0
}
}]
});
var rec = new MyApp.model.User();
var viewModel = new Ext.app.ViewModel({
data: {
theUser: rec
}
});
viewModel.bind({
dirty: '{theUser.dirty}',
phantom: '{theUser.phantom}',
valid: '{theUser.valid}'
}, function(v) {
console.log(v.dirty, v.valid);
});
rec.set('name', 'Foo');
viewModel.notify(); // dirty, not valid
rec.set('age', 20);
viewModel.notify(); // dirty, valid
rec.reject();
viewModel.notify(); // not dirty, not valid
For accessing other record information that is not exposed by the binding API, formulas can be used to achieve more advanced operations:
Ext.define('MyApp.model.User', {
extend: 'Ext.data.Model',
fields: ['name', 'age']
});
var rec = new MyApp.model.User();
var viewModel = new Ext.app.ViewModel({
formulas: {
isNameModified: {
bind: {
bindTo: '{theUser}',
deep: true
},
get: function(rec) {
return rec.isModified('name');
}
}
},
data: {
theUser: rec
}
});
viewModel.bind('{isNameModified}', function(modified) {
console.log(modified);
});
rec.set('name', 'Foo');
In the same way as fields, the bindings can also traverse associations in a bind statement.
The ViewModel
will handle the asynchronous loading of data and only present the value once
the full path has been loaded. For more information on associations see Ext.data.schema.OneToOne and
Ext.data.schema.ManyToOne associations.
Ext.define('User', {
extend: 'Ext.data.Model',
fields: ['name']
});
Ext.define('Order', {
extend: 'Ext.data.Model',
fields: ['date', {
name: 'userId',
reference: 'User'
}]
});
Ext.define('OrderItem', {
extend: 'Ext.data.Model',
fields: ['price', 'qty', {
name: 'orderId',
reference: 'Order'
}]
});
var viewModel = new Ext.app.ViewModel({
links: {
orderItem: {
type: 'OrderItem',
id: 13
}
}
});
// The viewmodel will handle both ways of loading the data:
// a) If the data is loaded inline in a nested fashion it will
// not make requests for extra data
// b) Only loading a single model at a time. So the Order will be loaded once
// the OrderItem returns. The User will be loaded once the Order loads.
viewModel.bind('{orderItem.order.user.name}', function(name) {
console.log(name);
});
Stores can be created as part of the ViewModel
definition. The definitions are processed
like bindings which allows for very powerful dynamic functionality.
It is important to ensure that you name viewModel's data keys uniquely. If data is not named uniquely, binds and formulas may receive information from an unintended data source. This applies to keys in the viewModel's data block, stores, and links configs.
var viewModel = new Ext.app.ViewModel({
stores: {
users: {
model: 'User',
autoLoad: true,
filters: [{
property: 'createdDate',
value: '{createdFilter}',
operator: '>'
}]
}
}
});
// Later on in our code, we set the date so that the store is created.
viewModel.set('createdFilter', Ext.Date.subtract(new Date(), Ext.Date.DAY, 7));
See stores for more detail.
It is possible to bind to the certain state properties of the store. The available options are:
Example:
Ext.define('MyApp.model.User', {
extend: 'Ext.data.Model',
fields: ['name']
});
var viewModel = new Ext.app.ViewModel({
stores: {
users: {
model: 'MyApp.model.User',
data: [{
name: 'Foo'
}, {
name: 'Bar'
}]
}
}
});
viewModel.bind('{users.first}', function(first) {
console.log(first ? first.get('name') : 'Nobody');
});
var timer = Ext.interval(function() {
var store = viewModel.getStore('users');
if (store.getCount()) {
store.removeAt(0);
} else {
Ext.uninterval(timer);
}
}, 100);
For accessing other store information that is not exposed by the binding API, formulas can be used to achieve more advanced operations:
Ext.define('MyApp.model.User', {
extend: 'Ext.data.Model',
fields: ['name', 'score']
});
var viewModel = new Ext.app.ViewModel({
stores: {
users: {
model: 'MyApp.model.User',
data: [{
name: 'Foo',
score: 100
}, {
name: 'Bar',
score: 350
}]
}
},
formulas: {
totalScore: {
bind: {
bindTo: '{users}',
deep: true
},
get: function(store) {
return store.sum('score');
}
}
}
});
viewModel.bind('{totalScore}', function(score) {
console.log(score);
});
viewModel.notify();
viewModel.getStore('users').removeAll();
Formulas allow for calculated ViewModel
data values. The dependencies for these formulas
are automatically determined so that the formula will not be processed until the required
data is present.
var viewModel = new Ext.app.ViewModel({
formulas: {
fullName: function(get) {
return get('firstName') + ' ' + get('lastName');
}
},
data: {firstName: 'John', lastName: 'Smith'}
});
viewModel.bind('{fullName}', function(v) {
console.log(v);
});
See formulas for more detail.
ViewModels can have a parent which allows values to be consumed from a shared base. These values that are available from the parent are not copied, rather they are "inherited" in a similar fashion to a javascript closure scope chain. This is demonstrated in the example below:
var parent = new Ext.app.ViewModel({
data: {
foo: 3
}
});
var child = new Ext.app.ViewModel({
parent: parent
});
This is analogous to the following javascript closure:
var foo = 3;
Ext.Ajax.request({
success: function() {
// foo is available here
}
});
In line with the above, the default behaviour when setting the value of a child ViewModel (either) through set or Ext.app.bind.Binding#method-setValue is to climb to where the value is "owned" and set the value there:
var parent = new Ext.app.ViewModel({
data: {
foo: 3
}
});
var child = new Ext.app.ViewModel({
parent: parent
});
child.set('foo', 100); // Climbs to set the value on parent
console.log(parent.get('foo')); // 100
parent.set('foo', 200);
console.log(child.get('foo')); // 200, inherited from the parent
Any subsequent sets are also inherited in the same fashion. The inheriting/climbing behavior occurs for any arbitrary depth, climbing/inherting can owned by a parent at any level above.
function log() {
console.log([a, b, c, d, e].map(function(vm) {
return vm.get('foo');
}));
}
var a = new Ext.app.ViewModel({data: {foo: 3}}),
b = new Ext.app.ViewModel({parent: a}),
c = new Ext.app.ViewModel({parent: b}),
d = new Ext.app.ViewModel({parent: c}),
e = new Ext.app.ViewModel({parent: d});
log(); // [3, 3, 3, 3, 3]
e.set('foo', 100);
log(); // [100, 100, 100, 100, 100]
This same climbing behavior applies when setting a value on a binding. The climbing begins from the ViewModel where the binding was attached:
function log() {
console.log([a, b, c].map(function(vm) {
return vm.get('foo');
}));
}
var a = new Ext.app.ViewModel({data: {foo: 3}}),
b = new Ext.app.ViewModel({parent: a}),
c = new Ext.app.ViewModel({parent: b});
var bind = c.bind('{foo}', function() {});
bind.setValue(100);
log(); // [100, 100, 100]
The exception to this rule is when there is nothing above to climb to. If a value is set and there is no parent above to hold it, then the value is set where it was called:
function log() {
console.log([a, b, c].map(function(vm) {
return vm.get('foo');
}));
}
var a = new Ext.app.ViewModel(),
b = new Ext.app.ViewModel({parent: a}),
c = new Ext.app.ViewModel({parent: b});
c.set('foo', 3);
log(); // [null, null, 3]
b.set('foo', 2);
log(); // [null, 2, 3]
a.set('foo', 1);
log(); // [1, 2, 3]
These values are called local values, which are discussed below.
If the child ViewModel is declared with top level data that also exists in the parent, then that child is considered to own that local value, so no value is inherited from the parent, nor does the climbing behaviour occur.
var parent = new Ext.app.ViewModel({
data: {
foo: 3
}
});
var child = new Ext.app.ViewModel({
parent: parent,
data: {
foo: 5
}
});
console.log(parent.get('foo'), child.get('foo')); // 3, 5
child.set('foo', 100);
console.log(parent.get('foo'), child.get('foo')); // 3, 100
parent.set('foo', 200);
console.log(parent.get('foo'), child.get('foo')); // 200, 100
The inheriting/climbing behavior is limited to local values:
function log() {
console.log([a, b, c, d, e].map(function(vm) {
return vm.get('foo');
}));
}
var a = new Ext.app.ViewModel({data: {foo: 1}}),
b = new Ext.app.ViewModel({parent: a}),
c = new Ext.app.ViewModel({parent: b, data: {foo: 2}}),
d = new Ext.app.ViewModel({parent: c}),
e = new Ext.app.ViewModel({parent: d, data: {foo: 3}});
log(); // [1, 1, 2, 2, 3]
e.set('foo', 100);
log(); // [1, 1, 2, 2, 100]
d.set('foo', 200);
log(); // [1, 1, 200, 200, 100]
c.set('foo', 201);
log(); // [1, 1, 201, 201, 100]
b.set('foo', 300);
log(); // [300, 300, 201, 201, 100]
a.set('foo', 301);
log(); // [301, 301, 201, 201, 100]
To bypass the climbing behaviour and push a value into a particular point in the hierarchy, the setData method should be used. Once a local value is set, it will be used as such in the future.
function log() {
console.log([a, b, c, d, e].map(function(vm) {
return vm.get('foo');
}));
}
var a = new Ext.app.ViewModel({data: {foo: 3}}),
b = new Ext.app.ViewModel({parent: a}),
c = new Ext.app.ViewModel({parent: b}),
d = new Ext.app.ViewModel({parent: c}),
e = new Ext.app.ViewModel({parent: d});
log(); // [3, 3, 3, 3, 3]
c.setData({
foo: 100
});
log(); // [3, 3, 100, 100, 100]
d.set('foo', 200); // Climbs to new local value
log(); // [3, 3, 200, 200, 200]
Similarly, data can be cleared from being a local value by setting the value to undefined:
function log() {
console.log([a, b, c, d].map(function(vm) {
return vm.get('foo');
}));
}
var a = new Ext.app.ViewModel({data: {foo: 3}}),
b = new Ext.app.ViewModel({parent: a}),
c = new Ext.app.ViewModel({parent: b, data: {foo: 100}}),
d = new Ext.app.ViewModel({parent: c});
log(); // [3, 3, 100, 100]
c.setData({
foo: undefined
});
log([3, 3, 3, 3]);