End time default value

README.md

@@ -50,6 +50,22 @@ const App = () => {
 };
 ```
 
+### Two and more timers
+
+```tsx
+import React from 'react';
+import { useTimer } from 'use-timer';
+
+const App = () => {
+  const { time: firstTimer, start: startFirstTimer, pause: pauseFirstTimer } = useTimer();
+  const { time: secondTimer, start: startSecondTimer, pause: pauseSecondTimer } = useTimer();
+
+  return (
+    ...
+  );
+};
+```
+
 ### Decremental timer
 
 ```tsx
@@ -113,13 +129,13 @@ const { time, start, pause, reset, status } = useTimer({
 
 The configuration and all its parameters are optional.
 
-| Property     | Type     | Default value | Description                                                                            |
-| ------------ | -------- | ------------- | -------------------------------------------------------------------------------------- |
-| autostart    | boolean  | false         | Pass true to start timer automatically                                                 |
-| endTime      | number   | null          | The value for which timer stops                                                        |
-| initialTime  | number   | 0             | The starting value for the timer                                                       |
-| interval     | number   | 1000          | The interval in milliseconds                                                           |
-| onTimeOver   | function |               | Callback function that is called when time is over                                     |
-| onTimeUpdate | function |               | Callback function that is called when time is updated                                  |
-| step         | number   | 1             | The value to add to each increment / decrement                                         |
-| timerType    | string   | "INCREMENTAL" | The choice between a value that increases ("INCREMENTAL") or decreases ("DECREMENTAL") |
+| Property     | Type     | Default value | Description                                                                                                                   |
+| ------------ | -------- | ------------- | ------------------------------------------------------------------------------------------------------------------------------|
+| autostart    | boolean  | false         | Pass true to start timer automatically                                                                                        |
+| endTime      | number   | null || 0     | The value for which timer stops. Null by default if timerType is "INCREMENTAL" and 0 by default if timerType is "DECREMENTAL" |
+| initialTime  | number   | 0             | The starting value for the timer                                                                                              |
+| interval     | number   | 1000          | The interval in milliseconds                                                                                                  |
+| onTimeOver   | function |               | Callback function that is called when time is over                                                                            |
+| onTimeUpdate | function |               | Callback function that is called when time is updated                                                                         |
+| step         | number   | 1             | The value to add to each increment / decrement                                                                                |
+| timerType    | string   | "INCREMENTAL" | The choice between a value that increases ("INCREMENTAL") or decreases ("DECREMENTAL")                                        |

src/useTimer.test.tsx

@@ -198,6 +198,35 @@ describe('Stop', () => {
     // Then
     expect(getByTestId('time').textContent).toBe('10');
   });
+
+  it('should stop decremental timer when time is 0', () => {
+    // Given
+    const Component = () => {
+      const { time, start } = useTimer({
+        initialTime: 30,
+        timerType: 'DECREMENTAL',
+      });
+
+      return (
+        <div>
+          <button onClick={start}>Start</button>
+          <p data-testid="time">{time}</p>
+        </div>
+      );
+    };
+
+    const { getByRole, getByTestId } = render(<Component />);
+
+    // When
+    fireEvent.click(getByRole('button'));
+
+    act(() => {
+      jest.advanceTimersByTime(30000);
+    });
+
+    // Then
+    expect(getByTestId('time').textContent).toBe('0');
+  });
 });
 
 describe('Pause', () => {

src/useTimer.ts

@@ -4,13 +4,13 @@ import reducer from './state/reducer';
 
 export const useTimer = ({
   autostart = false,
-  endTime,
+  timerType = 'INCREMENTAL',
+  endTime = timerType === 'INCREMENTAL' ? null : 0,
   initialTime = 0,
   interval = 1000,
   onTimeOver,
   onTimeUpdate,
   step = 1,
-  timerType = 'INCREMENTAL',
 }: Partial<Config> = {}): ReturnValue => {
   const [state, dispatch] = useReducer(reducer, {
     status: 'STOPPED',