# Class: DynamicList

## LuCI.ui. DynamicList

The `DynamicList` class implements a widget which allows the user to specify an arbitrary amount of input values, either from free formed text input or from a set of predefined choices.

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.DynamicList`. To import it in external JavaScript, use `L.require("ui").then(...)` and access the `DynamicList` property of the class instance value.

#### new LuCI.ui.DynamicList(value, choices, options)

ui.js, line 2102

  Instantiate a dynamic list widget.

  Name | Type | Default | Description
  --- | --- | --- | ---
  `value` | string | Array.<string> | null | optional The initial input value(s).
  `choices` | Object.<string, *> |  | optional Object containing the selectable choices of the widget. The object keys serve as values for the different choices while the values are used as choice labels. If omitted, no default choices are presented to the user, instead a plain text input field is rendered allowing the user to add arbitrary values to the dynamic list.
  `options` | LuCI.ui.DynamicList.InitOptions |  | optional Object describing the widget specific options to initialize the dynamic list.

### Extends

- LuCI.ui.AbstractElement

### Methods

#### addChoices(values, labels)

ui.js, line 2439

  Add new suggested choices to the dynamic list.

  This function adds further choices to an existing dynamic list, ignoring choice values which are already present.

  Name | Type | Description
  --- | --- | ---
  `values` | Array.<string> | The choice values to add to the dynamic lists suggestion dropdown.
  `labels` | Object.<string, *> | The choice label values to use when adding suggested choices. If no label is found for a particular choice value, the value itself is used as label text. Choice labels may be any valid value accepted by `LuCI.dom#content`.

#### clearChoices()

ui.js, line 2452

  Remove all existing choices from the dynamic list.

  This function removes all preexisting suggested choices from the widget.

#### inherited getValue(){string|Array.<string>|null}

ui.js, line 2390

  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.

#### inherited isChanged(){boolean}

ui.js, line 141

  Check whether the input value was altered by the user.

  ##### Returns:

  Type | Description
  --- | ---
  boolean | Returns `true` if the input value has been altered by the user or `false` if it is unchaged. Note that if the user modifies the initial value and changes it back to the original state, it is still reported as changed.

#### inherited isValid(){boolean}

ui.js, line 154

  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.

#### inherited registerEvents(targetNode, synevent, events)

ui.js, line 203

  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.

#### inherited render(){Node}

ui.js, line 2171

  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.

#### inherited setChangeEvents(targetNode, events)

ui.js, line 271

  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.

#### inherited setPlaceholder(value)

ui.js, line 113

  Set the current placeholder value of the input widget.

  Name | Type | Description
  --- | --- | ---
  `value` | string | Array.<string> | null | The placeholder to set for the input element. Only applicable to text inputs, not to radio buttons, selects or similar.

#### inherited setUpdateEvents(targetNode, events)

ui.js, line 228

  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.

#### inherited setValue(value)

ui.js, line 2407

  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.

#### inherited triggerValidation()

ui.js, line 168

  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.DynamicList.InitOptionsLuCI.ui.Dropdown.InitOptions

  In case choices are passed to the dynamic list contructor, the widget supports the same properties as `Dropdown.InitOptions` but enforces specific values for some dropdown properties.

  ##### Properties:

  Name | Type | Default | Description
  --- | --- | --- | ---
  `multiple` | boolean | false | Since dynamic lists never allow selecting multiple choices when adding another list item, this property is forcibly set to `false`.
  `optional` | boolean | true | Since dynamic lists use an embedded dropdown to present a list of predefined choice values, the dropdown must be made optional to allow it to remain unselected.