A mixin which adds scrolling capabilities to a widget.
When mixed into a host widget, this mixin brings scrolling capabilities based on the overflow: auto CSS property.
By default, the scrolling capabilities are added to the widget
node itself. The host widget can chose the node thanks to the property
scrollableNode
which must be set at latest in its render()
method.
During interactive or programmatic scrolling, native "scroll"
events are emitted, and can be listened to as follows (here,
scrollWidget
is the widget into which this mixin is mixed):
scrollWidget.on("scroll", function (event) {
...
});
For widgets that customize the scrollableNode
property,
the events should be listened to on widget.scrollableNode
:
scrollWidget.on("scroll", function (event) {
...
}, scrollWidget.scrollableNode);
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Extends
Show inheritedMembers
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<protected> attached :boolean
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Set to true when
attachedCallback()
has completed, and false whendetachedCallback()
called.Type:
- boolean
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<protected> baseClass :string
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Root CSS class of the widget (ex: "d-text-box")
Type:
- string
- Inherited From:
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<protected> created :boolean
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Set to true when
createdCallback()
has completed.Type:
- boolean
- Inherited From:
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dir :string
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Controls the layout direction of the widget, for example whether the arrow of a Combobox appears to the right or the left of the input field.
Values are "ltr" and "rtl", or "" which means that the value is inherited from the setting on the document root (either
<html>
or<body>
).Type:
- string
- Inherited From:
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<readonly> effectiveDir :string
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Actual direction of the widget, which can be set explicitly via
dir
property or inherited from the setting on the document root (either<html>
or<body>
). Value is either "ltr" or "rtl".Type:
- string
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<protected> focused :boolean
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This widget or a widget it contains has focus, or is "active" because it was recently clicked.
Type:
- boolean
- Inherited From:
- Default Value:
- false
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scrollableNode :Element
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Designates the descendant node of this widget which is made scrollable.
If not set otherwise before the
render()
method of the mixin is executed, it is set by default to this widget itself (this
).Note that this property can be set only at construction time, at latest in the
render()
method of the host widget into which this class is mixed. It should not be changed afterwards. Typically, this property can be set by a host widget which needs scrolling capabilities on one its descendant nodes.Type:
- Element
- Default Value:
- null
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scrollDirection :string
-
The direction of the interactive scroll. Possible values are: "vertical", "horizontal", "both, and "none".
Note that scrolling programmatically using
scrollTo()
is possible on both horizontal and vertical directions independently on the value ofscrollDirection
.Type:
- string
- Default Value:
- "vertical"
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<protected> template :function
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Value returned by delite/handlebars! or compatible template engine. Specifies how to build the widget DOM initially and also how to update the DOM when widget properties change.
Type:
- function
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<protected, constant> widgetId :number
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Unique id for this widget, separate from id attribute (which may or may not be set). Useful when widget creates subnodes that need unique id's.
Type:
- number
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Methods
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<protected> _get(name) → {*}
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Internal helper for directly accessing an attribute value.
Directly gets the value of an attribute on an object, bypassing any accessor getter. It is designed to be used by descendant class if they want to access the value in their custom getter before returning it.
Parameters:
Name Type Description name
string Name of property.
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Returns:
Value of property.
- Type
- *
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<protected> _set(name, value)
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Internal helper for directly setting a property value without calling the custom setter.
Directly changes the value of an attribute on an object, bypassing any accessor setter. Also notifies callbacks registered via observe(). Custom setters should call
_set
to actually record the new value.Parameters:
Name Type Description name
string The property to set.
value
* Value to set the property to.
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attachedCallback()
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Called automatically when the element is added to the document, after
createdCallback()
completes. This method is automatically chained, so subclasses generally do not need to usedcl.superCall()
,dcl.advise()
, etc.- Inherited From:
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Fires:
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computeProperties(oldValues, isAfterCreation)
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Callback function to calculate computed properties upon property changes.
Parameters:
Name Type Description oldValues
Object The hash table of old property values, keyed by property names.
isAfterCreation
boolean True if this call is right after instantiation.
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<protected> createdCallback()
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Called when the custom element is created, or when
register.parse()
parses a custom tag.This method is automatically chained, so subclasses generally do not need to use
dcl.superCall()
,dcl.advise()
, etc.- Inherited From:
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<protected> defer(fcn, delay) → {Object}
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Wrapper to setTimeout to avoid deferred functions executing after the originating widget has been destroyed.
Parameters:
Name Type Description fcn
function Function to be executed after specified delay (or 0ms if no delay specified).
delay
number Delay in ms, defaults to 0.
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Returns:
Handle with a remove method that deschedules the callback from being called.
- Type
- Object
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deliver()
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Synchronously deliver change records to all listeners registered via
observe()
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deliverComputing()
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Synchronously deliver change records for computed properties so that
computeProperties()
is called if there are pending change records.- Inherited From:
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destroy()
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Release resources used by this custom element and its descendants. After calling this method, the element can no longer be used, and should be removed from the document.
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detachedCallback()
-
Called when the element is removed the document. This method is automatically chained, so subclasses generally do not need to use
dcl.superCall()
,dcl.advise()
, etc.- Inherited From:
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discardChanges()
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Discard change records for all listeners registered via
observe()
.- Inherited From:
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discardComputing()
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Discard change records for computed properties.
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<protected> emit(type, eventObj) → {boolean}
-
Emits a synthetic event of specified type, based on eventObj.
Parameters:
Name Type Argument Description type
string Name of event.
eventObj
Object <optional>
Properties to mix in to emitted event. Can also contain
bubbles
andcancelable
properties to control how the event is emitted.- Inherited From:
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Returns:
True if the event was not canceled, false if it was canceled.
- Type
- boolean
Example
myWidget.emit("query-success", {});
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findCustomElements(root)
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Search subtree under root returning custom elements found.
Parameters:
Name Type Argument Description root
Element <optional>
Node to search under.
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getCurrentScroll() → {Object}
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Returns the current amount of scroll, as an object with x and y properties for the horizontal and vertical scroll amount. This is a convenience method and it is not supposed to be overridden.
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Returns:
- Type
- Object
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getEnclosingWidget(node)
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Returns the widget whose DOM tree contains the specified DOMNode, or null if the node is not contained within the DOM tree of any widget
Parameters:
Name Type Description node
Element - Inherited From:
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<protected> getInheritedDir() → {string}
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Get the direction setting for the page itself.
- Inherited From:
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Returns:
"ltr" or "rtl"
- Type
- string
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getParent()
-
Returns the parent widget of this widget, or null if there is no parent widget.
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<protected> getProps() → {Object}
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Returns a hash of properties that should be observed.
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Returns:
Hash of properties.
- Type
- Object
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<protected> getPropsToObserve() → {Array.<string>}
-
Get list of properties that Stateful#observe() should observe.
- Inherited From:
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Returns:
list of properties
- Type
- Array.<string>
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<protected> initializeInvalidating()
-
Make initial calls to
computeProperties()
,initializeRendering()
, andrefreshRendering()
, and setup observers so those methods are called whenever properties are modified in the future. Normally this method is called automatically by the constructor, and should not be called manually, but the method is exposed for custom elements since they do not call theconstructor()
method.- Inherited From:
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initializeRendering(oldValues)
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Callback function to initialize rendering.
Parameters:
Name Type Description oldValues
Object The hash table of old property values, keyed by property names.
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<protected> introspect(props)
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Sets up ES5 getters/setters for each class property. Inside introspect(), "this" is a reference to the prototype rather than any individual instance.
Parameters:
Name Type Description props
Object Hash of properties.
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isBottomScroll() → {boolean}
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Returns true if container's scroll has reached the maximum limit at the bottom of the contents. Returns false otherwise.
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Returns:
- Type
- boolean
Example
var scrollableNode = scrollableWidget.scrollableNode; scrollableNode.on("scroll", function () { if (scrollableWidget.isBottomScroll()) { console.log("Scroll reached the maximum limit at the bottom"); } }
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isLeftScroll() → {boolean}
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Returns true if container's scroll has reached the maximum limit at the left of the contents. Returns false otherwise.
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Returns:
- Type
- boolean
Example
var scrollableNode = scrollableWidget.scrollableNode; scrollableNode.on("scroll", function () { if (scrollableWidget.isLeftScroll()) { console.log("Scroll reached the maximum limit at the left"); } }
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isRightScroll() → {boolean}
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Returns true if container's scroll has reached the maximum limit at the right of the contents. Returns false otherwise.
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Returns:
- Type
- boolean
Example
var scrollableNode = scrollableWidget.scrollableNode; scrollableNode.on("scroll", function () { if (scrollableWidget.isRightScroll()) { console.log("Scroll reached the maximum limit at the right"); } }
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isTopScroll() → {boolean}
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Returns true if container's scroll has reached the maximum limit at the top of the contents. Returns false otherwise.
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Returns:
- Type
- boolean
Example
var scrollableNode = scrollableWidget.scrollableNode; scrollableNode.on("scroll", function () { if (scrollableWidget.isTopScroll()) { console.log("Scroll reached the maximum limit at the top"); } }
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mix(hash)
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Set a hash of properties on a Stateful instance.
Parameters:
Name Type Description hash
Object Hash of properties.
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Example
myObj.mix({ foo: "Howdy", bar: 3 });
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notifyCurrentValue(name)
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Notifies current values to observers for specified property name(s). Handy to manually schedule invocation of observer callbacks when there is no change in value.
Parameters:
Name Type Argument Description name
string <repeatable>
The property name.
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observe(callback) → {module:decor/Stateful.PropertyListObserver}
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Observes for change in properties. Callback is called at the end of micro-task of changes with a hash table of old values keyed by changed property. Multiple changes to a property in a micro-task are squashed.
Parameters:
Name Type Description callback
function The callback.
- Inherited From:
- Source:
Returns:
The observer that can be used to stop observation or synchronously deliver/discard pending change records.
Example
var stateful = new (dcl(Stateful, { foo: undefined, bar: undefined, baz: undefined }))({ foo: 3, bar: 5, baz: 7 }); stateful.observe(function (oldValues) { // oldValues is {foo: 3, bar: 5, baz: 7} }); stateful.foo = 4; stateful.bar = 6; stateful.baz = 8; stateful.foo = 6; stateful.bar = 8; stateful.baz = 10;
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on(type, func, node) → {Object}
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Call specified function when event occurs.
Note that the function is not run in any particular scope, so if (for example) you want it to run in the element's scope you must do
myCustomElement.on("click", myCustomElement.func.bind(myCustomElement))
.Note that
delite/Widget
overrideson()
so thaton("focus", ...)
and `on("blur", ...) will trigger the listener when focus moves into or out of the widget, rather than just when the widget's root node is focused/blurred. In other words, the listener is called when the widget is conceptually focused or blurred.Parameters:
Name Type Argument Description type
string Name of event (ex: "click").
func
function Callback function.
node
Element <optional>
Element to attach handler to, defaults to
this
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Returns:
Handle with
remove()
method to cancel the event.- Type
- Object
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<protected> own() → {Array.<Object>}
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Track specified handles and remove/destroy them when this instance is destroyed, unless they were already removed/destroyed manually.
- Inherited From:
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Returns:
The array of specified handles, so you can do for example:
var handle = this.own(on(...))[0];
- Type
- Array.<Object>
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<protected> parseAttribute(name, value)
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Helper for parsing declarative widgets. Interpret a given attribute specified in markup, returning either:
undefined
: ignore{prop: prop, value: value}
: setthis[prop] = value
{event: event, callback: callback}
: callthis.on(event, callback)
Parameters:
Name Type Description name
string Attribute name.
value
string Attribute value.
- Inherited From:
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<protected> parseFunctionAttribute(value, params)
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Helper to parse function attribute in markup. Unlike
_parsePrototypeAttr()
, does not require a corresponding widget property. Functions can be specified as global variables or as inline javascript:Parameters:
Name Type Description value
string Value of the attribute.
params
Array.<string> When generating a function from inline javascript, give it these parameter names.
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<protected> placeAt(reference, position) → {module:delite/Widget}
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Place this widget somewhere in the dom, and allow chaining.
Parameters:
Name Type Argument Description reference
string | Element | DocumentFragment Element, DocumentFragment, or id of Element to place this widget relative to.
position
string | number <optional>
Numeric index or a string with the values:
- number - place this widget as n'th child of
reference
node - "first" - place this widget as first child of
reference
node - "last" - place this widget as last child of
reference
node - "before" - place this widget as previous sibling of
reference
node - "after" - place this widget as next sibling of
reference
node - "replace" - replace specified reference node with this widget
- "only" - replace all children of
reference
node with this widget
- Inherited From:
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Returns:
This widget, for chaining.
- Type
- module:delite/Widget
Examples
// create a Button with no srcNodeRef, and place it in the body: var button = new Button({ label:"click" }).placeAt(document.body);
// place a new button as the first element of some div var button = new Button({ label:"click" }).placeAt("wrapper","first");
// create a contentpane and add it to a TabContainer var tc = document.getElementById("myTabs"); new ContentPane({ href:"foo.html", title:"Wow!" }).placeAt(tc)
- number - place this widget as n'th child of
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<protected> postRender()
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Processing after the DOM fragment is created.
Called after the DOM fragment has been created, but not necessarily added to the document. Do not include any operations which rely on node dimensions or placement.
This method is automatically chained, so subclasses generally do not need to use
dcl.superCall()
,dcl.advise()
, etc.- Inherited From:
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<protected> preRender()
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Processing before
render()
.This method is automatically chained, so subclasses generally do not need to use
dcl.superCall()
,dcl.advise()
, etc.- Inherited From:
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<protected> processConstructorParameters()
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Called after Object is created to process parameters passed to constructor.
- Inherited From:
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refreshRendering(oldValues, isAfterInitialRendering)
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Callback function to render UI upon property changes.
Parameters:
Name Type Description oldValues
Object The hash table of old property values, keyed by property names.
isAfterInitialRendering
boolean True if this call is right after
initializeRendering()
.- Inherited From:
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<protected> render()
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Construct the UI for this widget, filling in subnodes and/or text inside of this. Most widgets will leverage delite/handlebars! to set
template
, rather than defining this method.- Inherited From:
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scrollBy(by, duration)
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Scrolls by the given amount.
Parameters:
Name Type Description by
Object The scroll amount. An object with x and/or y properties, for example
{x: 0, y: -5}
or{y: -29}
.duration
number Duration of scrolling animation in milliseconds. If 0 or unspecified, scrolls without animation.
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scrollTo(to, duration)
-
Scrolls to the given position.
Parameters:
Name Type Argument Description to
Object The scroll destination position. An object with w and/or y properties, for example
{x: 0, y: -5}
or{y: -29}
.duration
number <optional>
Duration of scrolling animation in milliseconds. If 0 or unspecified, scrolls without animation.
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<protected> setClassComponent(component, value, node)
-
Helper method to set a class (or classes) on a given node, removing the class (or classes) set by the previous call to
setClassComponent()
for the specified component and node. Used mainly by template.js to set classes without overwriting classes set by the user or other code (ex: CssState).Parameters:
Name Type Argument Description component
string Specifies the category.
value
string Class (or classes) to set.
node
HTMLElement <optional>
The node to set the property on; defaults to widget root node.
- Inherited From:
- Source:
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<protected> setOrRemoveAttribute(node, name, value)
-
Helper method to set/remove an attribute based on the given value:
- If value is undefined, the attribute is removed. Useful for attributes like aria-valuenow.
- If value is boolean, the attribute is set to "true" or "false". Useful for attributes like aria-selected.
- If value is a number, it's converted to a string.
Parameters:
Name Type Description node
Element The node to set the property on.
name
string Name of the property.
value
string Value of the property.
- Inherited From:
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shouldInitializeRendering(oldValues, isAfterCreation) → {boolean}
-
Function to return if rendering should be initialized. (Instead of making partial changes for post-initialization)
Parameters:
Name Type Description oldValues
Object The hash table of old property values, keyed by property names.
isAfterCreation
boolean True if this call is right after instantiation.
- Inherited From:
- Source:
Returns:
True if rendering should be initialized.
- Type
- boolean
Events
-
customelement-attached
-
Dispatched after the CustomElement has been attached. This is useful to be notified when an HTMLElement has been upgraded to a CustomElement and attached to the DOM, in particular on browsers supporting native Custom Element.
- Inherited From:
- Source:
Example
element.addEventListener("customelement-attached", function (evt) { console.log("custom element: "+evt.target.id+" has been attached"); });