Class: AbstractElement

LuCI .ui. AbstractElement

The AbstractElement class serves as abstract base for the different widgets implemented by LuCI.ui. It provides the common logic for getting and setting values, for checking the validity state and for wiring up required events.

UI widget instances are usually not supposed to be created by view code directly, instead they're implicitely created by LuCI.form when instantiating CBI forms.

This class is automatically instantiated as part of LuCI.ui. To use it in views, use 'require ui' and refer to ui.AbstractElement. To import it in external JavaScript, use L.require("ui").then(...) and access the AbstractElement property of the class instance value.

new LuCI.ui.AbstractElement()

ui.js, line 12

Methods

getValue(){string|Array.<string>|null} ui.js, line 71

Read the current value of the input widget.

Returns:

Type	Description
string \| Array.<string> \| null	The current value of the input element. For simple inputs like text fields or selects, the return value type will be a - possibly empty - string. Complex widgets such as `DynamicList` instances may result in an array of strings or `null` for unset values.

isValid(){boolean} ui.js, line 103

Check whether the current input value is valid.

Returns:

Type	Description
boolean	Returns `true` if the current input value is valid or `false` if it does not meet the validation constraints.

registerEvents(targetNode, synevent, events) ui.js, line 152

Dispatch a custom (synthetic) event in response to received events.

Sets up event handlers on the given target DOM node for the given event names that dispatch a custom event of the given type to the widget root DOM node.

The primary purpose of this function is to set up a series of custom uniform standard events such as widget-update, validation-success, validation-failure etc. which are triggered by various different widget specific native DOM events.

Name	Type	Description
`targetNode`	Node	Specifies the DOM node on which the native event listeners should be registered.
`synevent`	string	The name of the custom event to dispatch to the widget root DOM node.
`events`	Array.<string>	The native DOM events for which event handlers should be registered.

render(){Node} ui.js, line 239

Render the widget, setup event listeners and return resulting markup.

Returns:

Type	Description
Node	Returns a DOM Node or DocumentFragment containing the rendered widget markup.

setChangeEvents(targetNode, events) ui.js, line 220

Setup listeners for native DOM events that may change the widget value.

Sets up event handlers on the given target DOM node for the given event names which may cause the input value to change completely, such as change events in a select menu. In contrast to update events, such change events will not trigger input value validation but they may cause field dependencies to get re-evaluated and will mark the input widget as dirty.

Name	Type	Description
`targetNode`	Node	Specifies the DOM node on which the event listeners should be registered.
`events`	string	repeatable The DOM events for which event handlers should be registered.

setUpdateEvents(targetNode, events) ui.js, line 177

Setup listeners for native DOM events that may update the widget value.

Sets up event handlers on the given target DOM node for the given event names which may cause the input value to update, such as keyup or onclick events. In contrast to change events, such update events will trigger input value validation.

Name	Type	Description
`targetNode`	Node	Specifies the DOM node on which the event listeners should be registered.
`events`	string	repeatable The DOM events for which event handlers should be registered.

setValue(value) ui.js, line 89

Set the current value of the input widget.

Name	Type	Description
`value`	string \| Array.<string> \| null	The value to set the input element to. For simple inputs like text fields or selects, the value should be a - possibly empty - string. Complex widgets such as `DynamicList` instances may accept string array or `null` values.

triggerValidation() ui.js, line 117

Force validation of the current input value.

Usually input validation is automatically triggered by various DOM events bound to the input widget. In some cases it is required though to manually trigger validation runs, e.g. when programmatically altering values.

Type Definitions

LuCI.ui.AbstractElement.InitOptionsObject

Properties:

Name	Type	Argument	Default	Description
`id`	string	<optional>		Specifies the widget ID to use. It will be used as HTML `id` attribute on the toplevel widget DOM node.
`name`	string	<optional>		Specifies the widget name which is set as HTML `name` attribute on the corresponding `<input>` element.
`optional`	boolean	<optional>	true	Specifies whether the input field allows empty values.
`datatype`	string	<optional>	string	An expression describing the input data validation constraints. It defaults to `string` which will allow any value. See`LuCI.validation` for details on the expression format.
`validator`	function	<optional>		Specifies a custom validator function which is invoked after the standard validation constraints are checked. The function should return `true` to accept the given input value. Any other return value type is converted to a string and treated as validation error message.