Bindings (#3326)

First draft of the new bindings API. We'll follow this up with some API
refinements, tests, documentation, and examples.

Bindings are a new record type for establishing relationships between
two shapes so they can update at the same time.

### Change Type

- [x] `sdk` — Changes the tldraw SDK
- [x] `feature` — New feature

### Release Notes

#### Breaking changes
- The `start` and `end` properties on `TLArrowShape` no longer have
`type: point | binding`. Instead, they're always a point, which may be
out of date if a binding exists. To check for & retrieve arrow bindings,
use `getArrowBindings(editor, shape)` instead.
- `getArrowTerminalsInArrowSpace` must be passed a `TLArrowBindings` as
a third argument: `getArrowTerminalsInArrowSpace(editor, shape,
getArrowBindings(editor, shape))`
- The following types have been renamed:
    - `ShapeProps` -> `RecordProps`
    - `ShapePropsType` -> `RecordPropsType`
    - `TLShapePropsMigrations` -> `TLPropsMigrations`
    - `SchemaShapeInfo` -> `SchemaPropsInfo`

---------

Co-authored-by: David Sheldrick <d.j.sheldrick@gmail.com>

packages/editor/src/lib/config/createTLStore.ts

@@ -1,13 +1,6 @@
 import { HistoryEntry, MigrationSequence, SerializedStore, Store, StoreSchema } from '@tldraw/store'
-import {
-	SchemaShapeInfo,
-	TLRecord,
-	TLStore,
-	TLStoreProps,
-	TLUnknownShape,
-	createTLSchema,
-} from '@tldraw/tlschema'
-import { TLShapeUtilConstructor } from '../editor/shapes/ShapeUtil'
+import { SchemaPropsInfo, TLRecord, TLStore, TLStoreProps, createTLSchema } from '@tldraw/tlschema'
+import { TLAnyBindingUtilConstructor, checkBindings } from './defaultBindings'
 import { TLAnyShapeUtilConstructor, checkShapesAndAddCore } from './defaultShapes'
 
 /** @public */
@@ -16,7 +9,11 @@ export type TLStoreOptions = {
 	defaultName?: string
 	id?: string
 } & (
-	| { shapeUtils?: readonly TLAnyShapeUtilConstructor[]; migrations?: readonly MigrationSequence[] }
+	| {
+			shapeUtils?: readonly TLAnyShapeUtilConstructor[]
+			migrations?: readonly MigrationSequence[]
+			bindingUtils?: readonly TLAnyBindingUtilConstructor[]
+	  }
 	| { schema?: StoreSchema<TLRecord, TLStoreProps> }
 )
 
@@ -41,9 +38,12 @@ export function createTLStore({
 				rest.schema
 			: // we need a schema
 				createTLSchema({
-					shapes: currentPageShapesToShapeMap(
+					shapes: utilsToMap(
 						checkShapesAndAddCore('shapeUtils' in rest && rest.shapeUtils ? rest.shapeUtils : [])
 					),
+					bindings: utilsToMap(
+						checkBindings('bindingUtils' in rest && rest.bindingUtils ? rest.bindingUtils : [])
+					),
 					migrations: 'migrations' in rest ? rest.migrations : [],
 				})
 
@@ -57,9 +57,9 @@ export function createTLStore({
 	})
 }
 
-function currentPageShapesToShapeMap(shapeUtils: TLShapeUtilConstructor<TLUnknownShape>[]) {
+function utilsToMap<T extends SchemaPropsInfo & { type: string }>(utils: T[]) {
 	return Object.fromEntries(
-		shapeUtils.map((s): [string, SchemaShapeInfo] => [
+		utils.map((s): [string, SchemaPropsInfo] => [
 			s.type,
 			{
 				props: s.props,