feat: update useSnapPoints to improve drawer snapping behavior and add new features

core/stdlib/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@robonen/stdlib",
-  "version": "0.0.11",
+  "version": "0.0.12",
   "license": "Apache-2.0",
   "description": "A collection of tools, utilities, and helpers for TypeScript",
   "keywords": [

core/stdlib/src/patterns/behavioral/StateMachine/index.test-d.ts

@@ -21,4 +21,28 @@ describe('createMachine', () => {
   it('send returns the (typed) resulting state', () => {
     expectTypeOf(machine.send('START')).toEqualTypeOf<'idle' | 'running'>();
   });
+
+  it('empty terminal nodes do not widen the event union to string', () => {
+    const terminal = createMachine({
+      initial: 'idle',
+      states: {
+        idle: { on: { START: 'done' } },
+        done: {},
+      },
+    });
+
+    expectTypeOf(terminal.send).parameter(0).toEqualTypeOf<'START'>();
+  });
+
+  it('entry/exit-only nodes do not widen the event union either', () => {
+    const hooked = createMachine({
+      initial: 'idle',
+      states: {
+        idle: { on: { START: 'done' } },
+        done: { entry: () => {} },
+      },
+    });
+
+    expectTypeOf(hooked.send).parameter(0).toEqualTypeOf<'START'>();
+  });
 });

core/stdlib/src/patterns/behavioral/StateMachine/index.test.ts

@@ -418,6 +418,7 @@ describe('asyncStateMachine', () => {
         },
       });
 
+      // @ts-expect-error -- deliberately undeclared event: runtime must ignore it
       const result = await machine.send('STOP');
 
       expect(result).toBe('idle');
@@ -597,6 +598,7 @@ describe('asyncStateMachine', () => {
         },
       });
 
+      // @ts-expect-error -- deliberately undeclared event: can() must report false
       expect(await machine.can('STOP')).toBe(false);
     });
 

core/stdlib/src/patterns/behavioral/StateMachine/types.ts

@@ -57,8 +57,12 @@ export type AsyncStateNodeConfig<Context> = StateNodeConfig<Context, MaybePromis
 
 export type ExtractStates<T> = keyof T & string;
 
+// `on` is matched as REQUIRED here on purpose: an empty terminal node (`{}`)
+// satisfies an optional-`on` pattern with no inference candidate, so `infer E`
+// would fall back to its constraint and collapse the whole union to `string`,
+// silently accepting any event name in `send`/`can`.
 export type ExtractEvents<T> = {
-  [K in keyof T]: T[K] extends { readonly on?: Readonly<Record<infer E extends string, unknown>> }
+  [K in keyof T]: T[K] extends { readonly on: Readonly<Record<infer E extends string, unknown>> }
     ? E
     : never;
 }[keyof T];