Bindings documentation (#3812)

Adds docs (reference material and a guide) for the bindings API. Also,
the unbind reason enum is now a union of strings.

### Change Type

- [x] `docs` — Changes to the documentation, examples, or templates.
- [x] `improvement` — Improving existing features

apps/docs/content/docs/editor.mdx

@@ -387,6 +387,108 @@ The camera may be in two states, `idle` or `moving`.
 
 You can get the current camera state with [Editor#getCameraState](?).
 
+# Bindings
+
+A binding is a relationship from one [shape](/docs/shapes) to another. They're used to connect
+shapes so they can update together or depend on one and other. For example: tldraw's default arrow
+shape uses bindings to connect the ends of the arrows to the shapes they're pointing to, one binding
+for each end of the arrow.
+
+You can create different types of binding that do all sorts of different things with relationships
+between shapes. For example, you could create a [sticker
+shape](/examples/shapes/tools/sticker-bindings) that sticks to any other shape it's dropped onto.
+
+## The binding object
+
+Bindings are records (JSON objects) that live in the [store](/docs/editor#store). For example,
+here's a binding record for one end of an arrow shape:
+
+```json
+{
+    "id": "binding:someId",
+    "typeName": "binding"
+    "type": "arrow",
+    "fromId": "shape:arrowId",
+    "toId": "shape:someOtherShapeId",
+    "props": {
+        "terminal": "end"
+        "isPrecise": true,
+        "isExact": false,
+        "normalizedAnchor": {
+            "x": 0.5,
+            "y": 0.5
+        },
+    },
+    "meta": {},
+}
+```
+
+Every binding contains some base information - its ID & the type of binding, as well as the ID of
+the shape that a binding comes _from_ and the ID of the shape that the binding goes _to_. These two
+properties work the same way, but it's often useful to have an explicit direction in a binding
+relationship. For example, an arrow binding always goes _from_ an arrow _to_ another shape.
+
+Bindings contain their own type-specific information in the `props` object. Each type of binding can
+have different props.
+
+Bindings also have a `meta` property which can be used by your application to add data to bindings
+you haven't built yourself. You can read more about the meta property
+[here](/docs/shapes#Meta-information).
+
+## Custom bindings
+
+To create a binding of your own, you can define a custom binding.
+
+### The binding type
+
+First, you need to create a type that describes what the binding object will look like:
+
+```ts
+import { TLBaseBinding } from 'tldraw'
+
+type StickerBinding = TLBaseBinding<'sticker', { x: number; y: number }>
+```
+
+With [TLBaseBinding](?) we define the binding's type (`sticker`) and `props` property (`{x: number,
+y: number}`). The type can be any string, and the props must be a plain JSON object (ie not a class
+instance).
+
+The [TLBaseBinding](?) helper adds the other base properties like `id`, `toId`, and `fromId`.
+
+### The `BindingUtil` class
+
+While bindings themselves are plain JSON objects, we use
+[`BindingUtil`](/reference/editor/BindingUtil) classes to define how bindings should work. They tell
+tldraw the structure of a binding, and what to do when it or the shapes it involves are created,
+updated, or deleted.
+
+```ts
+import { BindingUtil } from 'tldraw'
+
+class StickerBindingUtil extends BindingUtil<StickerBinding> {
+	static override type = 'sticker' as const
+
+	override getDefaultProps() {
+		return { x: 0.5, y: 0.5 }
+	}
+
+	override onAfterChangeToShape({ binding }) {
+		const sticker = this.editor.getShape(binding.fromShape)
+
+		// move the sticker so it stays attached to the to shape
+	}
+}
+```
+
+Each binding util needs a `type` and `getDefaultProps` to define its basic structure. You can also
+define a number of different callbacks describing how the binding should behave. See the
+[BindingUtil](?) reference or a [complete example of a
+binding](/examples/shapes/tools/sticker-bindings) for details.
+
+If the strucutre of your binding needs to change over time, you can provide
+[migrations](/docs/persistence#Shape-props-migrations) describing how old stored bindings can be
+brought up to date.
+
 # Common things to do with the editor
 
 ### Create a shape id

packages/editor/api-report.md

@@ -175,50 +175,39 @@ export abstract class BaseBoxShapeUtil<Shape extends TLBaseBoxShape> extends Sha
     onResize: TLOnResizeHandler<any>;
 }
 
-// @public (undocumented)
+// @public
 export interface BindingOnChangeOptions<Binding extends TLUnknownBinding> {
-    // (undocumented)
     bindingAfter: Binding;
-    // (undocumented)
     bindingBefore: Binding;
 }
 
-// @public (undocumented)
+// @public
 export interface BindingOnCreateOptions<Binding extends TLUnknownBinding> {
-    // (undocumented)
     binding: Binding;
 }
 
-// @public (undocumented)
+// @public
 export interface BindingOnDeleteOptions<Binding extends TLUnknownBinding> {
-    // (undocumented)
     binding: Binding;
 }
 
-// @public (undocumented)
+// @public
 export interface BindingOnShapeChangeOptions<Binding extends TLUnknownBinding> {
-    // (undocumented)
     binding: Binding;
-    // (undocumented)
     shapeAfter: TLShape;
-    // (undocumented)
     shapeBefore: TLShape;
 }
 
-// @public (undocumented)
+// @public
 export interface BindingOnShapeDeleteOptions<Binding extends TLUnknownBinding> {
-    // (undocumented)
     binding: Binding;
-    // (undocumented)
     shape: TLShape;
 }
 
-// @public (undocumented)
+// @public
 export interface BindingOnShapeIsolateOptions<Binding extends TLUnknownBinding> {
-    // (undocumented)
     binding: Binding;
-    // (undocumented)
+    removedShape: TLShape;
-    shape: TLShape;
 }
 
 // @public (undocumented)
@@ -229,31 +218,18 @@ export abstract class BindingUtil<Binding extends TLUnknownBinding = TLUnknownBi
     abstract getDefaultProps(): Partial<Binding['props']>;
     // (undocumented)
     static migrations?: TLPropsMigrations;
-    // (undocumented)
     onAfterChange?(options: BindingOnChangeOptions<Binding>): void;
-    // (undocumented)
     onAfterChangeFromShape?(options: BindingOnShapeChangeOptions<Binding>): void;
-    // (undocumented)
     onAfterChangeToShape?(options: BindingOnShapeChangeOptions<Binding>): void;
-    // (undocumented)
     onAfterCreate?(options: BindingOnCreateOptions<Binding>): void;
-    // (undocumented)
     onAfterDelete?(options: BindingOnDeleteOptions<Binding>): void;
-    // (undocumented)
     onBeforeChange?(options: BindingOnChangeOptions<Binding>): Binding | void;
-    // (undocumented)
     onBeforeCreate?(options: BindingOnCreateOptions<Binding>): Binding | void;
-    // (undocumented)
+    onBeforeDelete?(options: BindingOnDeleteOptions<Binding>): void;
-    onBeforeDelete?(options: BindingOnDeleteOptions<Binding>): Binding | void;
-    // (undocumented)
     onBeforeDeleteFromShape?(options: BindingOnShapeDeleteOptions<Binding>): void;
-    // (undocumented)
     onBeforeDeleteToShape?(options: BindingOnShapeDeleteOptions<Binding>): void;
-    // (undocumented)
     onBeforeIsolateFromShape?(options: BindingOnShapeIsolateOptions<Binding>): void;
-    // (undocumented)
     onBeforeIsolateToShape?(options: BindingOnShapeIsolateOptions<Binding>): void;
-    // (undocumented)
     onOperationComplete?(): void;
     // (undocumented)
     static props?: RecordProps<TLUnknownBinding>;
@@ -790,9 +766,7 @@ export class Editor extends EventEmitter<TLEventMap> {
     // @internal (undocumented)
     crash(error: unknown): this;
     createAssets(assets: TLAsset[]): this;
-    // (undocumented)
     createBinding<B extends TLBinding = TLBinding>(partial: TLBindingCreate<B>): this;
-    // (undocumented)
     createBindings(partials: TLBindingCreate[]): this;
     // @internal (undocumented)
     createErrorAnnotations(origin: string, willCrashApp: 'unknown' | boolean): {
@@ -811,9 +785,7 @@ export class Editor extends EventEmitter<TLEventMap> {
     createShape<T extends TLUnknownShape>(shape: OptionalKeys<TLShapePartial<T>, 'id'>): this;
     createShapes<T extends TLUnknownShape>(shapes: OptionalKeys<TLShapePartial<T>, 'id'>[]): this;
     deleteAssets(assets: TLAsset[] | TLAssetId[]): this;
-    // (undocumented)
     deleteBinding(binding: TLBinding | TLBindingId, opts?: Parameters<this['deleteBindings']>[1]): this;
-    // (undocumented)
     deleteBindings(bindings: (TLBinding | TLBindingId)[], { isolateShapes }?: {
         isolateShapes?: boolean | undefined;
     }): this;
@@ -860,13 +832,9 @@ export class Editor extends EventEmitter<TLEventMap> {
     getAssetForExternalContent(info: TLExternalAssetContent): Promise<TLAsset | undefined>;
     getAssets(): (TLBookmarkAsset | TLImageAsset | TLVideoAsset)[];
     getBaseZoom(): number;
-    // (undocumented)
     getBinding(id: TLBindingId): TLBinding | undefined;
-    // (undocumented)
     getBindingsFromShape<Binding extends TLUnknownBinding = TLBinding>(shape: TLShape | TLShapeId, type: Binding['type']): Binding[];
-    // (undocumented)
     getBindingsInvolvingShape<Binding extends TLUnknownBinding = TLBinding>(shape: TLShape | TLShapeId, type?: Binding['type']): Binding[];
-    // (undocumented)
     getBindingsToShape<Binding extends TLUnknownBinding = TLBinding>(shape: TLShape | TLShapeId, type: Binding['type']): Binding[];
     getBindingUtil<S extends TLUnknownBinding>(binding: {
         type: S['type'];
@@ -1141,9 +1109,7 @@ export class Editor extends EventEmitter<TLEventMap> {
         select: boolean;
     }>): this;
     updateAssets(assets: TLAssetPartial[]): this;
-    // (undocumented)
     updateBinding<B extends TLBinding = TLBinding>(partial: TLBindingUpdate<B>): this;
-    // (undocumented)
     updateBindings(partials: (null | TLBindingUpdate | undefined)[]): this;
     updateCurrentPageState(partial: Partial<Omit<TLInstancePageState, 'editingShapeId' | 'focusedGroupId' | 'pageId' | 'selectedShapeIds'>>, historyOptions?: TLHistoryBatchOptions): this;
     // (undocumented)
@@ -2181,9 +2147,7 @@ export interface TLBaseEventInfo {
 export interface TLBindingUtilConstructor<T extends TLUnknownBinding, U extends BindingUtil<T> = BindingUtil<T>> {
     // (undocumented)
     new (editor: Editor): U;
-    // (undocumented)
     migrations?: TLPropsMigrations;
-    // (undocumented)
     props?: RecordProps<T>;
     // (undocumented)
     type: T['type'];

packages/editor/src/lib/editor/Editor.ts

@@ -492,10 +492,10 @@ export class Editor extends EventEmitter<TLEventMap> {
 							deleteBindingIds.push(binding.id)
 							const util = this.getBindingUtil(binding)
 							if (binding.fromId === shape.id) {
-								util.onBeforeIsolateToShape?.({ binding, shape })
+								util.onBeforeIsolateToShape?.({ binding, removedShape: shape })
 								util.onBeforeDeleteFromShape?.({ binding, shape })
 							} else {
-								util.onBeforeIsolateFromShape?.({ binding, shape })
+								util.onBeforeIsolateFromShape?.({ binding, removedShape: shape })
 								util.onBeforeDeleteToShape?.({ binding, shape })
 							}
 						}
@@ -5152,10 +5152,17 @@ export class Editor extends EventEmitter<TLEventMap> {
 		})
 	}
 
+	/**
+	 * Get a binding from the store by its ID if it exists.
+	 */
 	getBinding(id: TLBindingId): TLBinding | undefined {
 		return this.store.get(id) as TLBinding | undefined
 	}
 
+	/**
+	 * Get all bindings of a certain type _from_ a particular shape. These are the bindings whose
+	 * `fromId` matched the shape's ID.
+	 */
 	getBindingsFromShape<Binding extends TLUnknownBinding = TLBinding>(
 		shape: TLShape | TLShapeId,
 		type: Binding['type']
@@ -5165,6 +5172,11 @@ export class Editor extends EventEmitter<TLEventMap> {
 			(b) => b.fromId === id && b.type === type
 		) as Binding[]
 	}
+
+	/**
+	 * Get all bindings of a certain type _to_ a particular shape. These are the bindings whose
+	 * `toId` matches the shape's ID.
+	 */
 	getBindingsToShape<Binding extends TLUnknownBinding = TLBinding>(
 		shape: TLShape | TLShapeId,
 		type: Binding['type']
@@ -5174,6 +5186,11 @@ export class Editor extends EventEmitter<TLEventMap> {
 			(b) => b.toId === id && b.type === type
 		) as Binding[]
 	}
+
+	/**
+	 * Get all bindings involving a particular shape. This includes bindings where the shape is the
+	 * `fromId` or `toId`. If a type is provided, only bindings of that type are returned.
+	 */
 	getBindingsInvolvingShape<Binding extends TLUnknownBinding = TLBinding>(
 		shape: TLShape | TLShapeId,
 		type?: Binding['type']
@@ -5184,6 +5201,10 @@ export class Editor extends EventEmitter<TLEventMap> {
 		return result.filter((b) => b.type === type) as Binding[]
 	}
 
+	/**
+	 * Create bindings from a list of partial bindings. You can omit the ID and most props of a
+	 * binding, but the `type`, `toId`, and `fromId` must all be provided.
+	 */
 	createBindings(partials: TLBindingCreate[]) {
 		const bindings: TLBinding[] = []
 		for (const partial of partials) {
@@ -5209,10 +5230,20 @@ export class Editor extends EventEmitter<TLEventMap> {
 		this.store.put(bindings)
 		return this
 	}
+
+	/**
+	 * Create a single binding from a partial. You can omit the ID and most props of a binding, but
+	 * the `type`, `toId`, and `fromId` must all be provided.
+	 */
 	createBinding<B extends TLBinding = TLBinding>(partial: TLBindingCreate<B>) {
 		return this.createBindings([partial])
 	}
 
+	/**
+	 * Update bindings from a list of partial bindings. Each partial must include an ID, which will
+	 * be used to match the binding to it's existing record. If there is no existing record, that
+	 * binding is skipped. The changes from the partial are merged into the existing record.
+	 */
 	updateBindings(partials: (TLBindingUpdate | null | undefined)[]) {
 		const updated: TLBinding[] = []
 
@@ -5238,10 +5269,18 @@ export class Editor extends EventEmitter<TLEventMap> {
 		return this
 	}
 
+	/**
+	 * Update a binding from a partial binding. Each partial must include an ID, which will be used
+	 * to match the binding to it's existing record. If there is no existing record, that binding is
+	 * skipped. The changes from the partial are merged into the existing record.
+	 */
 	updateBinding<B extends TLBinding = TLBinding>(partial: TLBindingUpdate<B>) {
 		return this.updateBindings([partial])
 	}
 
+	/**
+	 * Delete several bindings by their IDs. If a binding ID doesn't exist, it's ignored.
+	 */
 	deleteBindings(bindings: (TLBinding | TLBindingId)[], { isolateShapes = false } = {}) {
 		const ids = bindings.map((binding) => (typeof binding === 'string' ? binding : binding.id))
 		if (isolateShapes) {
@@ -5250,8 +5289,8 @@ export class Editor extends EventEmitter<TLEventMap> {
 					const binding = this.getBinding(id)
 					if (!binding) continue
 					const util = this.getBindingUtil(binding)
-					util.onBeforeIsolateFromShape?.({ binding, shape: this.getShape(binding.fromId)! })
+					util.onBeforeIsolateFromShape?.({ binding, removedShape: this.getShape(binding.toId)! })
-					util.onBeforeIsolateToShape?.({ binding, shape: this.getShape(binding.toId)! })
+					util.onBeforeIsolateToShape?.({ binding, removedShape: this.getShape(binding.fromId)! })
 					this.store.remove([id])
 				}
 			})
@@ -5260,6 +5299,9 @@ export class Editor extends EventEmitter<TLEventMap> {
 		}
 		return this
 	}
+	/**
+	 * Delete a binding by its ID. If the binding doesn't exist, it's ignored.
+	 */
 	deleteBinding(binding: TLBinding | TLBindingId, opts?: Parameters<this['deleteBindings']>[1]) {
 		return this.deleteBindings([binding], opts)
 	}

packages/editor/src/lib/editor/bindings/BindingUtil.ts

@@ -8,42 +8,110 @@ export interface TLBindingUtilConstructor<
 > {
 	new (editor: Editor): U
 	type: T['type']
+	/** Validations for this binding's props. */
 	props?: RecordProps<T>
+	/** Migrations for this binding's props. */
 	migrations?: TLPropsMigrations
 }
 
-/** @public */
+/**
+ * Options passed to {@link BindingUtil.onBeforeCreate} and {@link BindingUtil.onAfterCreate},
+ * describing a the creating a binding.
+ *
+ * @public
+ */
 export interface BindingOnCreateOptions<Binding extends TLUnknownBinding> {
+	/** The binding being created. */
 	binding: Binding
 }
 
-/** @public */
+/**
+ * Options passed to {@link BindingUtil.onBeforeChange} and {@link BindingUtil.onAfterChange},
+ * describing the data associated with a binding being changed.
+ *
+ * @public
+ */
 export interface BindingOnChangeOptions<Binding extends TLUnknownBinding> {
+	/** The binding record before the change is made. */
 	bindingBefore: Binding
+	/** The binding record after the change is made. */
 	bindingAfter: Binding
 }
 
-/** @public */
+/**
+ * Options passed to {@link BindingUtil.onBeforeDelete} and {@link BindingUtil.onAfterDelete},
+ * describing a binding being deleted.
+ *
+ * @public
+ */
 export interface BindingOnDeleteOptions<Binding extends TLUnknownBinding> {
+	/** The binding being deleted. */
 	binding: Binding
 }
 
-/** @public */
+/**
+ * Options passed to {@link BindingUtil.onAfterChangeFromShape} and
+ * {@link BindingUtil.onAfterChangeToShape}, describing a bound shape being changed.
+ *
+ * @public
+ */
 export interface BindingOnShapeChangeOptions<Binding extends TLUnknownBinding> {
+	/** The binding record linking these two shapes. */
 	binding: Binding
+	/** The shape record before the change is made. */
 	shapeBefore: TLShape
+	/** The shape record after the change is made. */
 	shapeAfter: TLShape
 }
 
-/** @public */
+/**
+ * Options passed to {@link BindingUtil.onBeforeIsolateFromShape} and
+ * {@link BindingUtil.onBeforeIsolateToShape}, describing a shape that is about to be isolated from
+ * the one that it's bound to.
+ *
+ * Isolation happens whenever two bound shapes are separated. For example
+ * 1. One is deleted, but the other is not.
+ * 1. One is copied, but the other is not.
+ * 1. One is duplicated, but the other is not.
+ *
+ * In each of these cases, if the remaining shape depends on the binding for its rendering, it may
+ * now be in an inconsistent state. For example, tldraw's arrow shape depends on the binding to know
+ * where the end of the arrow is. If we removed the binding without doing anything else, the arrow
+ * would suddenly be pointing to the wrong location. Instead, when the shape the arrow is pointing
+ * to is deleted, or the arrow is copied/duplicated, we use an isolation callback. The callback
+ * updates the arrow based on the binding that's about to be removed, so it doesn't end up pointing
+ * to the wrong place.
+ *
+ * For this style of consistency update, use isolation callbacks. For actions specific to deletion
+ * (like deleting a sticker when the shape it's bound to is removed), use the delete callbacks
+ * ({@link BindingUtil.onBeforeDeleteFromShape} and {@link BindingUtil.onBeforeDeleteToShape})
+ * instead.
+ *
+ * @public
+ */
 export interface BindingOnShapeIsolateOptions<Binding extends TLUnknownBinding> {
+	/** The binding record that refers to the shape in question. */
 	binding: Binding
-	shape: TLShape
+	/**
+	 * The shape being removed. For deletion, this is the deleted shape. For copy/duplicate, this is
+	 * the shape that _isn't_ being copied/duplicated and is getting left behind.
+	 */
+	removedShape: TLShape
 }
 
-/** @public */
+/**
+ * Options passed to {@link BindingUtil.onBeforeDeleteFromShape} and
+ * {@link BindingUtil.onBeforeDeleteToShape}, describing a bound shape that is about to be deleted.
+ *
+ * See {@link BindingOnShapeIsolateOptions} for discussion on when to use the delete vs. the isolate
+ * callbacks.
+ *
+ * @public
+ */
 export interface BindingOnShapeDeleteOptions<Binding extends TLUnknownBinding> {
+	/** The binding record that refers to the shape in question. */
 	binding: Binding
+	/** The shape that is about to be deleted. */
 	shape: TLShape
 }
 
@@ -67,22 +135,132 @@ export abstract class BindingUtil<Binding extends TLUnknownBinding = TLUnknownBi
 	 */
 	abstract getDefaultProps(): Partial<Binding['props']>
 
+	/**
+	 * Called whenever a store operation involving this binding type has completed. This is useful
+	 * for working with networks of related bindings that may need to update together.
+	 *
+	 * @example
+	 * ```ts
+	 * class MyBindingUtil extends BindingUtil<MyBinding> {
+	 *   changedBindingIds = new Set<TLBindingId>()
+	 *
+	 *   onOperationComplete() {
+	 *     doSomethingWithChangedBindings(this.changedBindingIds)
+	 *     this.changedBindingIds.clear()
+	 *   }
+	 *
+	 *   onAfterChange({ bindingAfter }: BindingOnChangeOptions<MyBinding>) {
+	 *     this.changedBindingIds.add(bindingAfter.id)
+	 *   }
+	 * }
+	 * ```
+	 *
+	 * @public
+	 */
 	onOperationComplete?(): void
 
-	// self lifecycle hooks
+	/**
+	 * Called when a binding is about to be created. See {@link BindingOnCreateOptions} for details.
+	 *
+	 * You can optionally return a new binding to replace the one being created - for example, to
+	 * set different initial props.
+	 *
+	 * @public
+	 */
 	onBeforeCreate?(options: BindingOnCreateOptions<Binding>): Binding | void
+
+	/**
+	 * Called after a binding has been created. See {@link BindingOnCreateOptions} for details.
+	 *
+	 * @public
+	 */
 	onAfterCreate?(options: BindingOnCreateOptions<Binding>): void
+
+	/**
+	 * Called when a binding is about to be changed. See {@link BindingOnChangeOptions} for details.
+	 *
+	 * Note that this only fires when the binding record is changing, not when the shapes
+	 * associated change. Use {@link BindingUtil.onAfterChangeFromShape} and
+	 * {@link BindingUtil.onAfterChangeToShape} for that.
+	 *
+	 * You can optionally return a new binding to replace the one being changed - for example, to
+	 * enforce constraints on the binding's props.
+	 *
+	 * @public
+	 */
 	onBeforeChange?(options: BindingOnChangeOptions<Binding>): Binding | void
+
+	/**
+	 * Called after a binding has been changed. See {@link BindingOnChangeOptions} for details.
+	 *
+	 * Note that this only fires when the binding record is changing, not when the shapes
+	 * associated change. Use {@link BindingUtil.onAfterChangeFromShape} and
+	 * {@link BindingUtil.onAfterChangeToShape} for that.
+	 *
+	 * @public
+	 */
 	onAfterChange?(options: BindingOnChangeOptions<Binding>): void
-	onBeforeDelete?(options: BindingOnDeleteOptions<Binding>): Binding | void
+
+	/**
+	 * Called when a binding is about to be deleted. See {@link BindingOnDeleteOptions} for details.
+	 *
+	 * @public
+	 */
+	onBeforeDelete?(options: BindingOnDeleteOptions<Binding>): void
+
+	/**
+	 * Called after a binding has been deleted. See {@link BindingOnDeleteOptions} for details.
+	 *
+	 * @public
+	 */
 	onAfterDelete?(options: BindingOnDeleteOptions<Binding>): void
 
+	/**
+	 * Called after the shape referenced in a binding's `fromId` is changed. Use this to propagate
+	 * any changes to the binding itself or the other shape as needed. See
+	 * {@link BindingOnShapeChangeOptions} for details.
+	 *
+	 * @public
+	 */
 	onAfterChangeFromShape?(options: BindingOnShapeChangeOptions<Binding>): void
+
+	/**
+	 * Called after the shape referenced in a binding's `toId` is changed. Use this to propagate any
+	 * changes to the binding itself or the other shape as needed. See
+	 * {@link BindingOnShapeChangeOptions} for details.
+	 *
+	 * @public
+	 */
 	onAfterChangeToShape?(options: BindingOnShapeChangeOptions<Binding>): void
 
-	onBeforeIsolateFromShape?(options: BindingOnShapeIsolateOptions<Binding>): void
+	/**
-	onBeforeIsolateToShape?(options: BindingOnShapeIsolateOptions<Binding>): void
+	 * Called before the shape referenced in a binding's `fromId` is about to be deleted. Use this
-
+	 * with care - you may want to use {@link BindingUtil.onBeforeIsolateToShape} instead. See
+	 * {@link BindingOnShapeDeleteOptions} for details.
+	 *
+	 * @public
+	 */
 	onBeforeDeleteFromShape?(options: BindingOnShapeDeleteOptions<Binding>): void
+	/**
+	 * Called before the shape referenced in a binding's `toId` is about to be deleted. Use this
+	 * with care - you may want to use {@link BindingUtil.onBeforeIsolateFromShape} instead. See
+	 * {@link BindingOnShapeDeleteOptions} for details.
+	 *
+	 * @public
+	 */
 	onBeforeDeleteToShape?(options: BindingOnShapeDeleteOptions<Binding>): void
+
+	/**
+	 * Called before the shape referenced in a binding's `fromId` is about to be isolated from the
+	 * shape referenced in `toId`. See {@link BindingOnShapeIsolateOptions} for discussion on what
+	 * isolation means, and when/how to use this callback.
+	 */
+	onBeforeIsolateFromShape?(options: BindingOnShapeIsolateOptions<Binding>): void
+
+	/**
+	 * Called before the shape referenced in a binding's `toId` is about to be isolated from the
+	 * shape referenced in `fromId`. See {@link BindingOnShapeIsolateOptions} for discussion on what
+	 * isolation means, and when/how to use this callback.
+	 */
+	onBeforeIsolateToShape?(options: BindingOnShapeIsolateOptions<Binding>): void
 }

packages/tlschema/api-report.md

@@ -959,7 +959,7 @@ export type TLBindingCreate<T extends TLBinding = TLBinding> = Expand<{
     typeName?: T['typeName'];
 }>;
 
-// @public (undocumented)
+// @public
 export type TLBindingId = RecordId<TLUnknownBinding>;
 
 // @public (undocumented)

packages/tlschema/src/records/TLBinding.ts

@@ -55,7 +55,11 @@ export type TLBindingCreate<T extends TLBinding = TLBinding> = Expand<{
 	meta?: Partial<T['meta']>
 }>
 
-/** @public */
+/**
+ * An ID for a {@link TLBinding}.
+ *
+ * @public
+ */
 export type TLBindingId = RecordId<TLUnknownBinding>
 
 /** @public */