react-native-biometric-verifier/src/hooks/useCountdown.js

A React Native module for biometric verification with face recognition and QR code scanning

import { useRef, useState, useEffect, useCallback } from 'react';
import { Global } from '../utils/Global';

/**
 * Custom hook for a countdown timer with pause/resume functionality.
 *
 * @param {Function} onExpire - Callback fired when countdown reaches zero.
 * @returns {Object} countdown, startCountdown, resetCountdown, pauseCountdown, resumeCountdown
 */
export const useCountdown = (onExpire) => {
  const [countdown, setCountdown] = useState(Global.CountdownDuration);
  const timerRef = useRef(null);
  const countdownRef = useRef(Global.CountdownDuration);
  const isPausedRef = useRef(false);
  const onExpireRef = useRef(onExpire);

  // Update onExpire callback reference
  useEffect(() => {
    onExpireRef.current = onExpire;
  }, [onExpire]);

  // Start or restart the countdown
  const startCountdown = useCallback((onExpireCallback) => {
    try {
      // Reset countdown
      countdownRef.current = Global.CountdownDuration;
      setCountdown(Global.CountdownDuration);
      isPausedRef.current = false;

      // Clear any existing timer
      if (timerRef.current) {
        clearInterval(timerRef.current);
        timerRef.current = null;
      }

      // Use provided callback or stored one
      const expireCallback = onExpireCallback || onExpireRef.current;

      // Start new timer
      timerRef.current = setInterval(() => {
        if (isPausedRef.current) return;

        countdownRef.current -= 1;

        if (countdownRef.current <= 0) {
          clearInterval(timerRef.current);
          timerRef.current = null;

          if (typeof expireCallback === 'function') {
            expireCallback();
          }
        } else {
          setCountdown(countdownRef.current);
        }
      }, 1000);
    } catch (error) {
      console.error('Error in startCountdown:', error);
    }
  }, []);

  // Pause the countdown
  const pauseCountdown = useCallback(() => {
    isPausedRef.current = true;
  }, []);

  // Resume the countdown
  const resumeCountdown = useCallback(() => {
    isPausedRef.current = false;
  }, []);

  // Reset countdown to initial duration
  const resetCountdown = useCallback(() => {
    try {
      countdownRef.current = Global.CountdownDuration;
      setCountdown(Global.CountdownDuration);
      isPausedRef.current = false;

      if (timerRef.current) {
        clearInterval(timerRef.current);
        timerRef.current = null;
      }
    } catch (error) {
      console.error('Error in resetCountdown:', error);
    }
  }, []);

  // Get current countdown value
  const getCurrentCountdown = useCallback(() => countdownRef.current, []);

  // Check if countdown is paused
  const isPaused = useCallback(() => isPausedRef.current, []);

  // Clean up on unmount
  useEffect(() => {
    return () => {
      if (timerRef.current) {
        clearInterval(timerRef.current);
        timerRef.current = null;
      }
    };
  }, []);

  return { 
    countdown, 
    startCountdown, 
    resetCountdown, 
    pauseCountdown, 
    resumeCountdown,
    getCurrentCountdown,
    isPaused
  };
};