feat: 🎸 implement timeout() utility

jest.config.js

@@ -1,6 +1,5 @@
 module.exports = {
   verbose: true,
-  testURL: 'http://localhost/',
   moduleFileExtensions: ['ts', 'tsx', 'js', 'jsx'],
   transform: {
     '^.+\.tsx?$': 'ts-jest',

src/__tests__/timeout.spec.ts

@@ -0,0 +1,39 @@
+import {timeout} from '../timeout';
+import {tick} from '../tick';
+
+test('returns result of the function', async () => {
+  const res = await timeout(1000, async () => 123);
+  expect(res).toBe(123);
+});
+
+test('returns result of the function - 2', async () => {
+  const res = await timeout(1000, async () => {
+    await tick(15);
+    return '123';
+  });
+  expect(res).toBe('123');
+});
+
+test('returns result of the promise', async () => {
+  const promise = (async () => {
+    await tick(15);
+    return '123';
+  })();
+  const res = await timeout(1000, promise);
+  expect(res).toBe('123');
+});
+
+test('throws TIMEOUT when running longer than timeout time', async () => {
+  const start = Date.now();
+  try {
+    await timeout(20, async () => {
+      await tick(500);
+      return '123';
+    });
+    throw 'not this';
+  } catch (error) {
+    expect(error).toEqual(new Error('TIMEOUT'));
+    const end = Date.now();
+    expect(end - start < 100).toBe(true);
+  }
+});

src/timeout.ts

@@ -0,0 +1,29 @@
+import type {Code} from "./types";
+
+/**
+ * Waits for given number of milliseconds before timing out. If provided code
+ * block does not complete within the given time, the promise will be rejected
+ * with `new Error('TIMEOUT')` error.
+ * 
+ * ```ts
+ * const result = await timeout(1000, async () => {
+ *   return 123;
+ * });
+ * ```
+ *
+ * @param ms Number of milliseconds to wait before timing out.
+ * @param code Code block or promise to execute.
+ * @returns The result of the code block or promise.
+ */
+export const timeout = <T>(ms: number, code: Code<T> | Promise<T>): Promise<T> =>
+  new Promise<T>((resolve, reject) => {
+    const timer: any = setTimeout(() => reject(new Error('TIMEOUT')), ms);
+    const promise = typeof code === 'function' ? code() : code;
+    promise.then((result) => {
+      clearTimeout(timer);
+      resolve(result);
+    }, (error) => {
+      clearTimeout(timer);
+      reject(error);
+    });
+  });