Mixin: module:delite/FormWidget

module:delite/FormWidget

Base class for widgets that extend HTMLElement, but conceptually correspond to native HTML elements such as <checkbox> or <button>, which can be children of a <form> node.

Note that FormWidget requires that this.focusNode be a sub-node of the widget, rather than the root node. This is because of its processing of tabIndex.

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Extends

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Members

alt :string

Corresponds to the native HTML <input> element's attribute.

Type:
  • string
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<protected> attached :boolean

Set to true when attachedCallback() has completed.

Type:
  • boolean
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<protected> baseClass :string

Root CSS class of the widget (ex: "d-text-box")

Type:
  • string
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<protected> created :boolean

Set to true when createdCallback() has completed.

Type:
  • boolean
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disabled :boolean

If set to true, the widget will not respond to user input and will not be included in form submission.

Type:
  • boolean
Default Value:
  • false
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<protected> focused :boolean

This widget or a widget it contains has focus, or is "active" because it was recently clicked.

Type:
  • boolean
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Default Value:
  • false
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name :string

Name used when submitting form; same as "name" attribute or plain HTML elements.

Type:
  • string
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<protected> started :boolean

Set to true when startup() has completed.

Type:
  • boolean
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tabIndex :number

The order in which fields are traversed when user hits the tab key.

Type:
  • number
Default Value:
  • 0
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tabStops :string

Comma separated list of tabbable nodes, i.e. comma separated list of widget properties that reference the widget DOM nodes that receive focus during tab operations.

Type:
  • string
Default Value:
  • "focusNode"
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<protected> template :function

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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value :string

Corresponds to the native HTML <input> element's attribute.

Type:
  • string
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<protected, constant> widgetId :number

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

<protected> _get(name) → {*}

Internal helper for directly accessing an attribute value.

Directly get 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
*

<protected> _set(name, value)

Internal helper for directly setting a property value without calling the custom setter.

Directly change 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()

Called when the element is added to the document, after createdCallback() completes. Note though that for programatically created custom elements, the app must manually call this method.

This method is automatically chained, so subclasses generally do not need to use dcl.superCall(), dcl.advise(), etc.

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computeProperties(newValues, oldValues)

Callback function to calculate computed properties upon property changes.

Parameters:
Name Type Description
newValues Object

The hash table of new property values, keyed by property names.

oldValues Object

The hash table of old property values, keyed by property names.

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<protected> createdCallback()

Kick off the life-cycle of a widget.

Calls a number of widget methods (preRender(), render(), and postRender()), some of which of you'll want to override.

Of course, adventurous developers could override createdCallback entirely, but this should only be done as a last resort.

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<protected> defer(fcn, delay) → {Object}

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

deliver()

Synchronously deliver change records for computed properties and then UI rendering so that refreshingRendering() is called if there are pending change records.

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deliverComputing()

Synchronously deliver change records for computed properties so that refreshingComputing() is called if there are pending change records.

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destroy()

Destroy this widget and its descendants.

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discardChanges()

Discard change records.

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discardComputing()

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 and cancelable properties to control how the event is emitted.

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Returns:

True if the event was not canceled, false if it was canceled.

Type
boolean
Example
myWidget.emit("query-success", {});

findCustomElements(root)

Search subtree under root returning custom elements found.

Parameters:
Name Type Argument Description
root Element <optional>

Node to search under.

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focus()

Put focus on this widget.

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getEnclosingWidget(node)

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
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getParent()

Returns the parent widget of this widget.

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<protected> initializeInvalidating()

Sets up observers, one for computed properties, one for UI rendering. 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 the constructor() method.

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<protected> isLeftToRight() → {boolean}

Return this widget's explicit or implicit orientation (true for LTR, false for RTL).

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Returns:
Type
boolean

mix(hash)

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
});

notifyCurrentValue(name)

Notify current value to observers. Handy to manually schedule invocation of observer callbacks when there is no change in value.

Parameters:
Name Type Description
name string

The property name.

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observe(callback) → {module:decor/Stateful.PropertyListObserver}

Observe 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 is squashed .

Parameters:
Name Type Description
callback function

The callback.

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Returns:

The observer that can be used to stop observation or synchronously deliver/discard pending change records.

Type
module:decor/Stateful.PropertyListObserver
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;

on(type, func, node) → {Object}

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 widget's scope you must do myWidget.on("click", myWidget.func.bind(myWidget)).

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

<protected> own() → {Array.<Object>}

Track specified handles and remove/destroy them when this instance is destroyed, unless they were already removed/destroyed manually.

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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>

<protected> parseAttribute(name, value)

Helper for parsing declarative widgets. Interpret a given attribute specified in markup, returning either:

  • undefined: ignore
  • {prop: prop, value: value}: set this[prop] = value
  • {event: event, callback: callback}: call this.on(event, callback)
Parameters:
Name Type Description
name string

Attribute name.

value string

Attribute value.

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<protected> parseFunctionAttribute(value, params)

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}

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
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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)

<protected> postRender()

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.

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<protected> preRender()

Processing before render().

This method is automatically chained, so subclasses generally do not need to use dcl.superCall(), dcl.advise(), etc.

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<protected> processConstructorParameters()

Called after Object is created to process parameters passed to constructor.

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refreshRendering(newValues, oldValues)

Callback function to render UI upon property changes.

Parameters:
Name Type Description
newValues Object

The hash table of new property values, keyed by property names.

oldValues Object

The hash table of old property values, keyed by property names.

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<protected> render()

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.

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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.

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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.

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startup()

Called after a widget and its children have been created and added to the page, and all related widgets have finished their creation cycle, up through postRender().

Most widgets should add initialization code to attachedCallback() rather than startup(). Code in startup() is only necessary for widgets that can't be initialized until related widgets have been created. For example, hypothetically, if DisplayContainer#selectedChildId could not be processed until the specified child DOM node existed, and had been upgraded from a plain DOM node into a widget. startup() may be removed in the future.

Note that startup() may be called while the widget is still hidden, for example if the widget is inside a hidden dialog or an unselected tab of a TabContainer, so the widget shouldn't try to do layout in startup().

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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.

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Example
element.addEventListener("customelement-attached", function (evt) {
     console.log("custom element: "+evt.target.id+" has been attached");
});