How to reset setInterval function using react hooks

Question

I'm using useInterval hook, wrote by Dan Abramov from here

How can I reset counter? As example by click on button?

Code on codesandbox

function Counter() {
  const [count, setCount] = useState(0);

  useInterval(() => {
    // Your custom logic here
    setCount(count + 1);
  }, 1000);

  const resetInterval = () => {};

  return (
    <>
      <h1>{count}</h1>
      <button ocClick={resetInterval}>Reset</button>
    </>
  );
}

Answer 1

To reset the counter, call setCount(0) from resetInterval:

Note: you misspelled onClick on the button.

function Counter() {
  const [count, setCount] = useState(0);

  useInterval(() => {
    // Your custom logic here
    setCount(count => count + 1);
  }, 1000);

  const resetInterval = () => setCount(0);

  return (
    <>
      <h1>{count}</h1>
      <button onClick={resetInterval}>Reset</button>
    </>
  );
}

To stop/resume the interval you can refactor useInterval to return a toggleRunning function, and the current running status.

function useInterval(callback, delay) {
  const savedCallback = useRef();
  const intervalId = useRef(null);
  const [currentDelay, setDelay] = useState(delay);

  const toggleRunning = useCallback(
    () => setDelay(currentDelay => (currentDelay === null ? delay : null)),
    [delay]
  );

  const clear = useCallback(() => clearInterval(intervalId.current), []);

  // Remember the latest function.
  useEffect(() => {
    savedCallback.current = callback;
  }, [callback]);

  // Set up the interval.
  useEffect(() => {
    function tick() {
      savedCallback.current();
    }

    if (intervalId.current) clear();

    if (currentDelay !== null) {
      intervalId.current = setInterval(tick, currentDelay);
    }

    return clear;
  }, [currentDelay, clear]);

  return [toggleRunning, !!currentDelay];
}

Working example with Reset and Pause/Resume (Sandbox)

const { useState, useEffect, useRef, useCallback, Fragment } = React;

function Counter() {
  const [count, setCount] = useState(0);

  const [toggle, running] = useInterval(() => {
    // Your custom logic here
    setCount(count => count + 1);
  }, 100);

  const resetCounter = () => setCount(0);

  return (
    <Fragment>
      <h1>{count}</h1>
      <button onClick={resetCounter}>Reset</button>
      <button onClick={toggle}>{running ? "Pause" : "Resume"}</button>
    </Fragment>
  );
}

function useInterval(callback, delay) {
  const savedCallback = useRef();
  const intervalId = useRef(null);
  const [currentDelay, setDelay] = useState(delay);

  const toggleRunning = useCallback(
    () => setDelay(currentDelay => (currentDelay === null ? delay : null)),
    [delay]
  );

  const clear = useCallback(() => clearInterval(intervalId.current), []);

  // Remember the latest function.
  useEffect(() => {
    savedCallback.current = callback;
  }, [callback]);

  // Set up the interval.
  useEffect(() => {
    function tick() {
      savedCallback.current();
    }

    if (intervalId.current) clear();

    if (currentDelay !== null) {
      intervalId.current = setInterval(tick, currentDelay);
    }

    return clear;
  }, [currentDelay, clear]);

  return [toggleRunning, !!currentDelay];
}

ReactDOM.render(<Counter />, root);

<script crossorigin src="https://unpkg.com/react@16/umd/react.development.js"></script>
<script crossorigin src="https://unpkg.com/react-dom@16/umd/react-dom.development.js"></script>

<div id="root"></div>