chore: Switch to vitest.

debounced/debounced.test.ts

@@ -1,15 +1,15 @@
 import { createDebounced } from './debounced.js';
 
 test('debounced', () => {
-  jest.useFakeTimers();
-  const callback = jest.fn();
+  vi.useFakeTimers();
+  const callback = vi.fn();
   const debounced = createDebounced(250, callback);
   debounced(1);
   expect(callback).toHaveBeenCalledTimes(1);
   expect(callback).toHaveBeenLastCalledWith(1);
   debounced(2);
   expect(callback).toHaveBeenCalledTimes(1);
-  jest.runAllTimers();
+  vi.runAllTimers();
   debounced(3);
   expect(callback).toHaveBeenCalledTimes(2);
   expect(callback).toHaveBeenLastCalledWith(3);

deferred/deferred.test.ts

@@ -1,14 +1,14 @@
 import { createDeferred } from './deferred.js';
 
 test('deferred', () => {
-  jest.useFakeTimers();
-  const callback = jest.fn();
+  vi.useFakeTimers();
+  const callback = vi.fn();
   const deferred = createDeferred(1000, callback);
   deferred(1);
   expect(callback).not.toHaveBeenCalled();
   deferred(2);
   expect(callback).not.toHaveBeenCalled();
-  jest.runAllTimers();
+  vi.runAllTimers();
   expect(callback).toHaveBeenCalledTimes(1);
   expect(callback).toHaveBeenLastCalledWith(2);
   deferred(3);
@@ -17,6 +17,6 @@ test('deferred', () => {
   expect(callback).toHaveBeenLastCalledWith(3);
   deferred(4);
   deferred.cancel();
-  jest.runAllTimers();
+  vi.runAllTimers();
   expect(callback).toHaveBeenCalledTimes(2);
 });

eslint.config.js

@@ -0,0 +1,5 @@
+import rational from 'eslint-config-rational';
+
+export default rational({
+  ignores: ['**/node_modules/', '**/lib/', '**/out/', '**/.*/'],
+});

events/events.test.ts

@@ -12,8 +12,8 @@ describe('Events', () => {
 
   test('emit calls listeners', () => {
     const events = new Events();
-    const a = jest.fn();
-    const b = jest.fn();
+    const a = vi.fn();
+    const b = vi.fn();
     const off = events.on('event', a);
     events.on('event', b);
     events.emit('event', 1, 2);
@@ -29,7 +29,7 @@ describe('Events', () => {
 
   test('emit only calls listeners for the emitted event', () => {
     const events = new Events();
-    const a = jest.fn();
+    const a = vi.fn();
     events.on('event', a);
     events.emit('other');
     expect(a).not.toHaveBeenCalled();

fetch-sdk/fetch-sdk.test.ts

@@ -12,14 +12,14 @@ describe('createFetchSdk', () => {
 
   beforeEach(() => {
     res.status = 200;
-    (global as any).fetch = jest.fn().mockResolvedValue(res);
+    (global as any).fetch = vi.fn().mockResolvedValue(res);
     (global as any).Request = class {
       constructor(url: string, init: Record<string, string>) {
         Object.assign(this, { url: String(url), ...init, headers: new Headers(init.headers as any) });
       }
     };
-    res.text = jest.fn().mockResolvedValue('');
-    res.json = jest.fn().mockResolvedValue({});
+    res.text = vi.fn().mockResolvedValue('');
+    res.json = vi.fn().mockResolvedValue({});
   });
 
   afterEach(() => {
@@ -41,7 +41,7 @@ describe('createFetchSdk', () => {
     });
 
     test('constructor with arguments', () => {
-      const definitions = jest.fn().mockReturnValue({});
+      const definitions = vi.fn().mockReturnValue({});
       const Sdk = createFetchSdk(definitions);
       new Sdk('foo', 123, true);
 
@@ -106,9 +106,9 @@ describe('createFetchSdk', () => {
           body: 'foo',
         }),
       );
-      expect(Object.fromEntries((jest.mocked(fetch).mock.lastCall?.[0] as any).headers.entries())).toEqual({
-        'x-foo': 'foo',
-      });
+      const args = vi.mocked(fetch).mock.lastCall!;
+      const request = args[0] as unknown as Request;
+      expect(request.headers.get('x-foo')).toBe('foo');
 
       await sdk.bar();
       expect(fetch).toHaveBeenLastCalledWith(
@@ -146,9 +146,9 @@ describe('createFetchSdk', () => {
       const Sdk = createFetchSdk({ foo: { url: 'https://example.com' } });
       const sdk = new Sdk();
       const reason = new Error('fetch');
-      jest.mocked(fetch).mockRejectedValue(reason);
+      vi.mocked(fetch).mockRejectedValue(reason);
       await expect(sdk.foo()).rejects.toMatchObject({
-        message: expect.stringMatching(/^failed fetching /),
+        message: expect.stringMatching(/^failed fetching /u),
         code: 'network_error',
         reason,
       });
@@ -158,7 +158,7 @@ describe('createFetchSdk', () => {
       const Sdk = createFetchSdk({ foo: { url: 'https://example.com', accept: () => false } });
       const sdk = new Sdk();
       await expect(sdk.foo()).rejects.toMatchObject({
-        message: expect.stringMatching(/^failed fetching /),
+        message: expect.stringMatching(/^failed fetching /u),
         code: 'unacceptable',
       });
     });
@@ -175,7 +175,7 @@ describe('createFetchSdk', () => {
       });
       const sdk = new Sdk();
       await expect(sdk.foo()).rejects.toMatchObject({
-        message: expect.stringMatching(/^failed fetching /),
+        message: expect.stringMatching(/^failed fetching /u),
         code: 'unacceptable',
         reason,
       });
@@ -186,7 +186,7 @@ describe('createFetchSdk', () => {
       const Sdk = createFetchSdk({ foo: { url: 'https://example.com' } });
       const sdk = new Sdk();
       await expect(sdk.foo()).rejects.toMatchObject({
-        message: expect.stringMatching(/^failed fetching /),
+        message: expect.stringMatching(/^failed fetching /u),
         code: 'unacceptable',
       });
     });
@@ -204,15 +204,15 @@ describe('createFetchSdk', () => {
       );
       const sdk = new Sdk();
       await expect(sdk.foo()).rejects.toMatchObject({
-        message: expect.stringMatching(/^failed fetching /),
+        message: expect.stringMatching(/^failed fetching /u),
         code: 'foo',
       });
       await expect(sdk.bar()).rejects.toMatchObject({
-        message: expect.stringMatching(/^failed fetching /),
+        message: expect.stringMatching(/^failed fetching /u),
         code: 'bar',
       });
       await expect(sdk.baz()).rejects.toMatchObject({
-        message: expect.stringMatching(/^failed fetching /),
+        message: expect.stringMatching(/^failed fetching /u),
         code: 1,
       });
     });
@@ -227,7 +227,7 @@ describe('createFetchSdk', () => {
       });
       const sdk = new Sdk();
       await expect(sdk.foo()).rejects.toMatchObject({
-        message: expect.stringMatching(/^failed fetching /),
+        message: expect.stringMatching(/^failed fetching /u),
         code: 'unacceptable',
       });
     });
@@ -242,7 +242,7 @@ describe('createFetchSdk', () => {
       });
       const sdk = new Sdk();
       await expect(sdk.foo()).rejects.toMatchObject({
-        message: expect.stringMatching(/^failed fetching /),
+        message: expect.stringMatching(/^failed fetching /u),
         code: 'parse_error',
         reason,
       });

fetch-sdk/fetch-sdk.ts

@@ -95,12 +95,12 @@ type FetchSdkInstance<TDefinitions extends FetchSdkRequests> = {
   [P in keyof TDefinitions]: TDefinitions[P] extends string
     ? FetchSdkFunction<Response, []>
     : TDefinitions[P] extends FetchSdkRequestFactory<any, infer TArgs>
-    ? ReturnType<TDefinitions[P]> extends { parse(...args: any[]): Promise<infer TResult> }
-      ? FetchSdkFunction<TResult, TArgs>
-      : FetchSdkFunction<Response, TArgs>
-    : TDefinitions[P] extends { parse(...args: any[]): Promise<infer TResult> }
-    ? FetchSdkFunction<TResult, []>
-    : FetchSdkFunction<Response, []>;
+      ? ReturnType<TDefinitions[P]> extends { parse(...args: any[]): Promise<infer TResult> }
+        ? FetchSdkFunction<TResult, TArgs>
+        : FetchSdkFunction<Response, TArgs>
+      : TDefinitions[P] extends { parse(...args: any[]): Promise<infer TResult> }
+        ? FetchSdkFunction<TResult, []>
+        : FetchSdkFunction<Response, []>;
 };
 
 type FetchSdkConstructor<TDefinitions extends FetchSdkRequests, TArgs extends any[]> = new (
@@ -172,10 +172,10 @@ class FetchSdkError extends Error {
  * ```
  */
 const createFetchSdk: {
-  <TDefinitions extends FetchSdkRequests>(definitions: TDefinitions, defaults?: FetchSdkDefaults): FetchSdkConstructor<
-    TDefinitions,
-    []
-  >;
+  <TDefinitions extends FetchSdkRequests>(
+    definitions: TDefinitions,
+    defaults?: FetchSdkDefaults,
+  ): FetchSdkConstructor<TDefinitions, []>;
   <TDefinitions extends FetchSdkRequests, TArgs extends any[] = []>(
     definitions: (...args: TArgs) => TDefinitions,
     defaults?: FetchSdkDefaults,

fsm/fsm.ts

@@ -13,8 +13,8 @@ type FsmTransition<
 > = TStates[TToState] extends undefined | void
   ? () => FsmState<TStates, TEdges, TToState>
   : undefined extends TStates[TToState]
-  ? (value?: TStates[TToState]) => FsmState<TStates, TEdges, TToState>
-  : (value: TStates[TToState]) => FsmState<TStates, TEdges, TToState>;
+    ? (value?: TStates[TToState]) => FsmState<TStates, TEdges, TToState>
+    : (value: TStates[TToState]) => FsmState<TStates, TEdges, TToState>;
 
 type FsmState<
   TStates extends FsmStatesDefinition = Readonly<Record<FsmStateKey, any>>,
@@ -43,8 +43,8 @@ type Fsm<TStates extends FsmStatesDefinition = FsmStatesDefinition, TEdges exten
     ...args: TStates[TState] extends undefined | void
       ? readonly []
       : undefined extends TStates[TState]
-      ? readonly [value?: TStates[TState]]
-      : readonly [value: TStates[TState]]
+        ? readonly [value?: TStates[TState]]
+        : readonly [value: TStates[TState]]
   ): FsmState<TStates, TEdges, TState>;
   transition<
     TAction extends string,
@@ -70,17 +70,17 @@ type Fsm<TStates extends FsmStatesDefinition = FsmStatesDefinition, TEdges exten
 type InferFsmStateKeys<TFsm> = TFsm extends Fsm<infer TStates>
   ? keyof TStates
   : TFsm extends FsmState<infer TStates>
-  ? keyof TStates
-  : never;
+    ? keyof TStates
+    : never;
 
 type InferFsmStates<TFsm, TStateSubset extends InferFsmStateKeys<TFsm> = InferFsmStateKeys<TFsm>> = TFsm extends Fsm<
   infer TStates,
   infer TEdges
 >
   ? FsmStatesUnion<TStates, TEdges, TStateSubset>
   : TFsm extends FsmState<infer TStates, infer TEdges>
-  ? FsmStatesUnion<TStates, TEdges, TStateSubset>
-  : never;
+    ? FsmStatesUnion<TStates, TEdges, TStateSubset>
+    : never;
 
 const createFsmState = (
   transitions: Readonly<Record<FsmStateKey, Readonly<Record<string, FsmTransition>>>>,

hello-world/hello-world.test.ts

@@ -3,7 +3,7 @@ import { hello } from './hello-world.js';
 describe('hello-world', () => {
   ['world', 'jane', 'john'].forEach((who) => {
     test(`who: ${who}`, () => {
-      jest.spyOn(console, 'log').mockImplementation();
+      vi.spyOn(console, 'log').mockImplementation(() => undefined);
       hello('world');
       expect(console.log).toHaveBeenCalledTimes(1);
       expect(console.log).toHaveBeenLastCalledWith('Hello, world!');

limiter/limiter.test.ts

@@ -3,11 +3,11 @@ import { createLimiter } from './limiter.js';
 
 const tasks: { reject(): void; resolve(): void }[] = [];
 const nextTick = (): Promise<void> => new Promise(process.nextTick);
-let task: jest.Mock;
+let task: any;
 
 beforeEach(() => {
   tasks.length = 0;
-  task = jest
+  task = vi
     .fn()
     .mockImplementation(
       (arg) =>

limiter/limiter.ts

@@ -70,7 +70,7 @@ const createLimiter = (concurrency: number, options: LimiterOptions = {}): Limit
   const update = (): void => {
     while (!isPaused && active < safeConcurrency && queue.length) {
       active += 1;
-      queue
+      void queue
         .shift()
         ?.start()
         .finally(() => {