@motion-script/core

@motion-script/core / RefTarget

Type Alias: RefTarget()<T>

RefTarget<T> = void

Defined in: util/reference.ts:45

A slot that can receive a T — a Reference<T>, or one declared as any supertype of T.

This is the type a node's ref prop takes, and the widening is deliberate: the framework only ever writes into a ref (props.ref(this) in the Node constructor) and the author only ever reads, so handing a Rect to a Reference<ShapeNode> is sound in both directions — the write stores a subtype, the read yields the supertype the author asked for. That is what lets one ref hold whichever shape a factory happened to build:

const ref = createRef<ShapeNode>();
<Rect ref={ref} />      // ✔ Rect is a ShapeNode
<Ellipse ref={ref} />   // ✔ so is Ellipse

The opposite direction stays an error, because it is the unsound one: a Reference<Rect> on a <Text> would be handed a Text at runtime while still typing every read as a Rect.

A plain setter function is accepted too, which makes React-style callback refs (ref={n => …}) work without a separate type.

Type Parameters

T

T

RefTarget(node): void

A slot that can receive a T — a Reference<T>, or one declared as any supertype of T.

This is the type a node's ref prop takes, and the widening is deliberate: the framework only ever writes into a ref (props.ref(this) in the Node constructor) and the author only ever reads, so handing a Rect to a Reference<ShapeNode> is sound in both directions — the write stores a subtype, the read yields the supertype the author asked for. That is what lets one ref hold whichever shape a factory happened to build:

const ref = createRef<ShapeNode>();
<Rect ref={ref} />      // ✔ Rect is a ShapeNode
<Ellipse ref={ref} />   // ✔ so is Ellipse

The opposite direction stays an error, because it is the unsound one: a Reference<Rect> on a <Text> would be handed a Text at runtime while still typing every read as a Rect.

A plain setter function is accepted too, which makes React-style callback refs (ref={n => …}) work without a separate type.

Parameters

node

T | null

Returns

void

Properties

__accepts?

readonly optional __accepts?: (node) => void

Defined in: util/reference.ts:47

Parameters

node

T

Returns

void