feat(shared/helpers): make Timeout pausable

Author: sidvishnoi

src/shared/__tests__/helpers.test.ts

@@ -7,6 +7,7 @@ import {
   getNextOccurrence,
   toWalletAddressUrl,
   setDifference,
+  Timeout,
 } from '../helpers';
 
 describe('objectEquals', () => {
@@ -165,3 +166,54 @@ describe('toWalletAddressUrl', () => {
     );
   });
 });
+
+describe('Timeout', () => {
+  jest.useFakeTimers();
+
+  let callback: jest.Mock;
+  let timeout: Timeout;
+  beforeEach(() => {
+    callback = jest.fn();
+    timeout = new Timeout(1000, callback);
+  });
+
+  afterEach(() => {
+    jest.clearAllTimers();
+    test;
+  });
+
+  it('should call the callback after the specified time', () => {
+    jest.advanceTimersByTime(1000);
+    expect(callback).toHaveBeenCalledTimes(1);
+  });
+
+  it('should reset the timeout', () => {
+    timeout.reset(2000);
+    // @ts-expect-error for testing it's ok to access private properties
+    expect(timeout.ms).toBe(2000);
+    jest.advanceTimersByTime(2000);
+    expect(callback).toHaveBeenCalledTimes(1);
+  });
+
+  it('should pause the timeout', () => {
+    timeout.pause();
+    jest.advanceTimersByTime(1000);
+    expect(callback).not.toHaveBeenCalled();
+  });
+
+  it('should resume the timeout', () => {
+    timeout.pause();
+    jest.advanceTimersByTime(500);
+    timeout.resume();
+    jest.advanceTimersByTime(500);
+    expect(callback).not.toHaveBeenCalled();
+    jest.advanceTimersByTime(500);
+    expect(callback).toHaveBeenCalledTimes(1);
+  });
+
+  it('should clear the timeout', () => {
+    timeout.clear();
+    jest.advanceTimersByTime(1000);
+    expect(callback).not.toHaveBeenCalled();
+  });
+});

src/shared/helpers/time.ts

@@ -116,20 +116,48 @@ export function debounceSync<T extends unknown[], R>(
 
 export class Timeout {
   private timeout: ReturnType<typeof setTimeout> | null = null;
+  #ms: number;
+  #isPaused = false;
+  #remaining = 0;
+  #startTime = 0;
+
   constructor(
     ms: number,
     private callback: () => void,
   ) {
-    this.reset(ms);
+    this.#ms = ms;
+    if (ms > 0) this.reset(ms);
   }
 
   reset(ms: number) {
     this.clear();
+    this.#ms = ms;
+    this.#isPaused = false;
+    this.#startTime = Date.now();
     this.timeout = setTimeout(this.callback, ms);
   }
 
+  pause() {
+    if (this.#isPaused) return;
+    this.clear();
+    this.#isPaused = true;
+    this.#remaining = this.#ms - (Date.now() - this.#startTime);
+  }
+
+  resume() {
+    if (!this.#isPaused) return;
+    if (this.#remaining > 0) {
+      this.timeout = setTimeout(() => {
+        this.callback();
+        this.reset(this.#ms);
+      }, this.#remaining);
+    } else {
+      this.reset(this.#ms);
+    }
+  }
+
   clear() {
-    if (this.timeout) {
+    if (this.timeout !== null) {
       clearTimeout(this.timeout);
       this.timeout = null;
     }