feat: SNAP events now have source

Fixes #87

README.md

@@ -140,7 +140,7 @@ iOS Safari, and some other mobile culprits, can be tricky if you're on a page th
 
 ## Events
 
-All events receive `SprinngEvent` as their argument. It has a single property, `type`, which can be `'OPEN' | 'RESIZE' | 'SNAP' | 'CLOSE'` depending on the scenario.
+All events receive `SpringEvent` as their argument. The payload varies, but `type` is always present, which can be `'OPEN' | 'RESIZE' | 'SNAP' | 'CLOSE'` depending on the scenario.
 
 ### onSpringStart
 
@@ -195,8 +195,26 @@ Fires whenever there's been a window resize event, or if the header, footer or c
 
 #### SNAP
 
+Type: `{ source: 'dragging' | 'custom' }`
+
 Fired after dragging ends, or when calling `ref.snapTo`, and a transition to a valid snap point is happening.
 
+`source` is `'dragging'` if the snapping is responding to a drag gesture that just ended. And it's set to `'custom'` when using `ref.snapTo`.
+
+```jsx
+function Example() {
+  return (
+    <BottomSheet
+      onSpringStart={async (event) => {
+        if (event.type === 'SNAP' && event.source === 'dragging') {
+          console.log('Starting a spring animation to user selected snap point')
+        }
+      }}
+    />
+  )
+}
+```
+
 ### onSpringEnd
 
 Type: `(event: SpringEvent) => void`

src/BottomSheet.tsx

@@ -168,7 +168,11 @@ export const BottomSheet = React.forwardRef<
         []
       ),
       onSnapCancel: useCallback(
-        () => onSpringCancelRef.current?.({ type: 'SNAP' }),
+        (context) =>
+          onSpringCancelRef.current?.({
+            type: 'SNAP',
+            source: context.snapSource,
+          }),
         []
       ),
       onCloseCancel: useCallback(
@@ -184,7 +188,11 @@ export const BottomSheet = React.forwardRef<
         []
       ),
       onSnapEnd: useCallback(
-        () => onSpringEndRef.current?.({ type: 'SNAP' }),
+        (context, event) =>
+          onSpringEndRef.current?.({
+            type: 'SNAP',
+            source: context.snapSource,
+          }),
         []
       ),
       onResizeEnd: useCallback(
@@ -195,7 +203,11 @@ export const BottomSheet = React.forwardRef<
     context: { initialState },
     services: {
       onSnapStart: useCallback(
-        async () => onSpringStartRef.current?.({ type: 'SNAP' }),
+        async (context, event) =>
+          onSpringStartRef.current?.({
+            type: 'SNAP',
+            source: event.payload.source || 'custom',
+          }),
         []
       ),
       onOpenStart: useCallback(
@@ -211,7 +223,11 @@ export const BottomSheet = React.forwardRef<
         []
       ),
       onSnapEnd: useCallback(
-        async () => onSpringEndRef.current?.({ type: 'SNAP' }),
+        async (context, event) =>
+          onSpringEndRef.current?.({
+            type: 'SNAP',
+            source: context.snapSource,
+          }),
         []
       ),
       onOpenEnd: useCallback(
@@ -463,7 +479,7 @@ export const BottomSheet = React.forwardRef<
     }
 
     if (last) {
-      send('SNAP', { payload: { y: newY, velocity } })
+      send('SNAP', { payload: { y: newY, velocity, source: 'dragging' } })
 
       return memo
     }

src/machines/overlay.ts

@@ -80,7 +80,14 @@ interface OverlayStateSchema {
 
 type OverlayEvent =
   | { type: 'OPEN' }
-  | { type: 'SNAP'; payload: { y: number; velocity: number } }
+  | {
+      type: 'SNAP'
+      payload: {
+        y: number
+        velocity: number
+        source: 'dragging' | 'custom' | string
+      }
+    }
   | { type: 'CLOSE' }
   | { type: 'DRAG' }
   | { type: 'RESIZE' }
@@ -191,6 +198,7 @@ export const overlayMachine = Machine<
                 // @ts-expect-error
                 y: (_, { payload: { y } }) => y,
                 velocity: (_, { payload: { velocity } }) => velocity,
+                snapSource: (_, { payload: { source = 'custom' } }) => source,
               }),
             ],
           },

src/types.ts

@@ -31,9 +31,11 @@ export type defaultSnapProps = {
 } & SnapPointProps
 
 /* Might make sense to expose a preventDefault method here */
-export type SpringEvent = {
-  type: 'OPEN' | 'CLOSE' | 'RESIZE' | 'SNAP'
-}
+export type SpringEvent =
+  | { type: 'OPEN' }
+  | { type: 'CLOSE' }
+  | { type: 'RESIZE' }
+  | { type: 'SNAP'; source: 'dragging' | 'custom' | string }
 
 export type Props = {
   /**