Interface: IToolboxItem

Defined in: packages/blockly/core/interfaces/i_toolbox_item.ts:15

Interface for an item in the toolbox.

Extends

• IFocusableNode

Extended by

• ISelectableToolboxItem

Methods index

Method	Description
getFocusableElement	Returns the DOM element that can be explicitly requested to receive focus.
getFocusableTree	Returns the closest parent tree of this node (in cases where a tree has distinct trees underneath it), which represents the tree to which this node belongs.
onNodeFocus	Called when this node receives active focus.
onNodeBlur	Called when this node loses active focus. It may still have passive focus.
canBeFocused	Indicates whether this node allows focus. If this returns false then none of the other IFocusableNode methods will be called.
performAction	Optional method invoked when this node has focus and the user acts on it by pressing Enter or Space. Behavior should generally be similar to the node being clicked on.
init	Initializes the toolbox item. This includes creating the DOM and updating the state of any items based on the info object.
getDiv	Gets the div for the toolbox item.
getId	Gets a unique identifier for this toolbox item.
getParent	Gets the parent if the toolbox item is nested.
isSelectable	Whether the toolbox item is selectable.
isCollapsible	Whether the toolbox item is collapsible.
dispose	Dispose of this toolbox item. No-op by default.
getClickTarget	Gets the HTML element that is clickable.
setVisible_	Sets whether the category is visible or not. For a category to be visible its parent category must also be expanded.
getParentToolbox	-

Methods

getFocusableElement()

getFocusableElement(): HTMLElement | SVGElement;

Defined in: packages/blockly/core/interfaces/i_focusable_node.ts:44

Returns the DOM element that can be explicitly requested to receive focus.

IMPORTANT: Please note that this element is expected to have a visual presence on the page as it will both be explicitly focused and have its style changed depending on its current focus state (i.e. blurred, actively focused, and passively focused). The element will have one of two styles attached (where no style indicates blurred/not focused):

• blocklyActiveFocus
• blocklyPassiveFocus

The returned element must also have a valid ID specified, and this ID should be unique across the entire page. Failing to have a properly unique ID could result in trying to focus one node (such as via a mouse click) leading to another node with the same ID actually becoming focused by FocusManager.

The returned element must be visible if the node is ever focused via FocusManager.focusNode() or FocusManager.focusTree(). It's allowed for an element to be hidden until onNodeFocus() is called, or become hidden with a call to onNodeBlur().

It's expected the actual returned element will not change for the lifetime of the node (that is, its properties can change but a new element should never be returned). Also, the returned element will have its tabindex overwritten throughout the lifecycle of this node and FocusManager.

If a node requires the ability to be focused directly without first being focused via FocusManager then it must set its own tab index.

Returns

HTMLElement | SVGElement

The HTMLElement or SVGElement which can both receive focus and be visually represented as actively or passively focused for this node.

Inherited from

IFocusableNode.getFocusableElement

---

getFocusableTree()

getFocusableTree(): IFocusableTree;

Defined in: packages/blockly/core/interfaces/i_focusable_node.ts:53

Returns the closest parent tree of this node (in cases where a tree has distinct trees underneath it), which represents the tree to which this node belongs.

Returns

IFocusableTree

The node's IFocusableTree.

Inherited from

IFocusableNode.getFocusableTree

---

onNodeFocus()

onNodeFocus(): void;

Defined in: packages/blockly/core/interfaces/i_focusable_node.ts:66

Called when this node receives active focus.

Note that it's fine for implementations to change visibility modifiers, but they should avoid the following:

• Creating or removing DOM elements (including via the renderer or drawer).
• Affecting focus via DOM focus() calls or the FocusManager.

Implementations may consider scrolling themselves into view here; that is not handled by the focus manager.

Returns

void

Inherited from

IFocusableNode.onNodeFocus

---

onNodeBlur()

onNodeBlur(): void;

Defined in: packages/blockly/core/interfaces/i_focusable_node.ts:73

Called when this node loses active focus. It may still have passive focus.

This has the same implementation restrictions as onNodeFocus().

Returns

void

Inherited from

IFocusableNode.onNodeBlur

---

canBeFocused()

canBeFocused(): boolean;

Defined in: packages/blockly/core/interfaces/i_focusable_node.ts:101

Indicates whether this node allows focus. If this returns false then none of the other IFocusableNode methods will be called.

Note that special care must be taken if implementations of this function dynamically change their return value value over the lifetime of the node as certain environment conditions could affect the focusability of this node's DOM element (such as whether the element has a positive or zero tabindex). Also, changing from a true to a false value while the node holds focus will not immediately change the current focus of the node nor FocusManager's internal state, and thus may result in some of the node's functions being called later on when defocused (since it was previously considered focusable at the time of being focused).

Implementations should generally always return true here unless there are circumstances under which this node should be skipped for focus considerations. Examples may include being disabled, read-only, a purely visual decoration, or a node with no visual representation that must implement this interface (e.g. due to a parent interface extending it). Keep in mind accessibility best practices when determining whether a node should be focusable since even disabled and read-only elements are still often relevant to providing organizational context to users (particularly when using a screen reader).

Returns

boolean

Whether this node can be focused by FocusManager.

Inherited from

IFocusableNode.canBeFocused

---

performAction()?

optional performAction(e?): void;

Defined in: packages/blockly/core/interfaces/i_focusable_node.ts:110

Optional method invoked when this node has focus and the user acts on it by pressing Enter or Space. Behavior should generally be similar to the node being clicked on.

Parameters

Parameter	Type	Description
e?	Event	The event that triggered this action, if any.

Returns

void

Inherited from

IFocusableNode.performAction

---

init()

init(): void;

Defined in: packages/blockly/core/interfaces/i_toolbox_item.ts:21

Initializes the toolbox item. This includes creating the DOM and updating the state of any items based on the info object.

Returns

void

---

getDiv()

getDiv(): Element | null;

Defined in: packages/blockly/core/interfaces/i_toolbox_item.ts:28

Gets the div for the toolbox item.

Returns

Element | null

The div for the toolbox item.

---

getId()

getId(): string;

Defined in: packages/blockly/core/interfaces/i_toolbox_item.ts:35

Gets a unique identifier for this toolbox item.

Returns

string

The ID for the toolbox item.

---

getParent()

getParent(): IToolboxItem | null;

Defined in: packages/blockly/core/interfaces/i_toolbox_item.ts:43

Gets the parent if the toolbox item is nested.

Returns

IToolboxItem | null

The parent toolbox item, or null if this toolbox item is not nested.

---

isSelectable()

isSelectable(): boolean;

Defined in: packages/blockly/core/interfaces/i_toolbox_item.ts:58

Whether the toolbox item is selectable.

Returns

boolean

True if the toolbox item can be selected.

---

isCollapsible()

isCollapsible(): boolean;

Defined in: packages/blockly/core/interfaces/i_toolbox_item.ts:65

Whether the toolbox item is collapsible.

Returns

boolean

True if the toolbox item is collapsible.

---

dispose()

dispose(): void;

Defined in: packages/blockly/core/interfaces/i_toolbox_item.ts:68

Dispose of this toolbox item. No-op by default.

Returns

void

---

getClickTarget()

getClickTarget(): Element | null;

Defined in: packages/blockly/core/interfaces/i_toolbox_item.ts:75

Gets the HTML element that is clickable.

Returns

Element | null

The HTML element that receives clicks.

---

setVisible_()

setVisible_(isVisible): void;

Defined in: packages/blockly/core/interfaces/i_toolbox_item.ts:83

Sets whether the category is visible or not. For a category to be visible its parent category must also be expanded.

Parameters

Parameter	Type	Description
isVisible	boolean	True if category should be visible.

Returns

void

---

getParentToolbox()

getParentToolbox(): IToolbox;

Defined in: packages/blockly/core/interfaces/i_toolbox_item.ts:85

Returns

IToolbox