A collection of zero-dependency useful hooks and components for React.

yarn add react-essentials-functions
# or
npm install react-essentials-functions

• Hooks
  • useClickOutside
  • useDebounce
  • useDimensions
  • useLocalStorage
  • useMediaQuery
  • usePrevious
  • useSafeFetch
  • useSafeState
  • useScript
  • useTheme
  • useToggle
  • useWindowDimensions
• Components
  • ConditionalWrapper

Hook that detects clicks outside of a referenced element. Useful for closing dropdowns, modals, and popovers. Listens for both mousedown and touchstart events.

Parameters:

• ref: RefObject<HTMLElement> - React ref to the element to monitor
• handler: (event: MouseEvent | TouchEvent) => void - Callback fired when a click outside is detected

Returns:

• void

Side effects:

• Adds mousedown and touchstart event listeners on document
• Removes listeners on unmount

Example:

import { useClickOutside } from 'react-essentials-functions';
import { useRef, useState } from 'react';

function Dropdown() {
  const dropdownRef = useRef<HTMLDivElement>(null);
  const [isOpen, setIsOpen] = useState(false);

  useClickOutside(dropdownRef, () => setIsOpen(false));

  return (
    <div ref={dropdownRef}>
      <button onClick={() => setIsOpen(true)}>Open</button>
      {isOpen && <ul><li>Option 1</li><li>Option 2</li></ul>}
    </div>
  );
}

Hook that debounces a value by a given delay. The debounced value will only update after the specified delay has passed since the last change. Useful for search inputs, API calls, and any rapid-fire updates.

Type Parameters:

• T - The type of the value to debounce

Parameters:

• value: T - The value to debounce
• delay: number - The debounce delay in milliseconds

Returns:

• T - The debounced value

Example:

import { useDebounce } from 'react-essentials-functions';
import { useState, useEffect } from 'react';

function SearchComponent() {
  const [searchTerm, setSearchTerm] = useState('');
  const debouncedSearch = useDebounce(searchTerm, 300);

  useEffect(() => {
    if (debouncedSearch) {
      // This only fires 300ms after the user stops typing
      fetchResults(debouncedSearch);
    }
  }, [debouncedSearch]);

  return (
    <input
      value={searchTerm}
      onChange={(e) => setSearchTerm(e.target.value)}
      placeholder="Search..."
    />
  );
}

Hook to get the dimensions of a DOM element. Uses ResizeObserver for optimal performance with a fallback to window events for older browsers.

Parameters:

• targetRef: RefObject<HTMLElement> - React ref to the element to measure

Returns:

• Dimensions - Object containing width and height of the element

Side effects:

• Creates a ResizeObserver on the target element (or falls back to resize/scroll window listeners)
• Cleans up on unmount

Example:

import { useDimensions } from 'react-essentials-functions';
import { useRef } from 'react';

function MyComponent() {
  const targetRef = useRef<HTMLDivElement>(null);
  const { width, height } = useDimensions(targetRef);

  return (
    <div ref={targetRef}>
      Size: {width}px x {height}px
    </div>
  );
}

Hook that syncs state with localStorage. Handles JSON serialization/deserialization automatically. Falls back gracefully when localStorage is unavailable (SSR, private browsing).

Type Parameters:

• T - The type of the stored value

Parameters:

• key: string - The localStorage key
• initialValue: T - The initial value if nothing is stored

Returns:

• [T, (value: T | ((prev: T) => T)) => void, () => void] - A tuple containing:
  • The current stored value
  • A setter function (accepts value or updater function)
  • A remove function to clear the key from localStorage

Side effects:

• Reads from localStorage on initialization
• Writes to localStorage on every value change
• removeValue deletes the key from localStorage

Example:

import { useLocalStorage } from 'react-essentials-functions';

function Settings() {
  const [name, setName, removeName] = useLocalStorage('user-name', '');
  const [preferences, setPreferences] = useLocalStorage('prefs', {
    notifications: true,
    language: 'en',
  });

  return (
    <div>
      <input value={name} onChange={(e) => setName(e.target.value)} />
      <button onClick={removeName}>Clear name</button>
      <button onClick={() => setPreferences(prev => ({ ...prev, language: 'fr' }))}>
        Switch to French
      </button>
    </div>
  );
}

Hook that tracks whether a CSS media query matches. Listens for changes and updates automatically. Useful for responsive design, detecting dark mode preference, reduced motion, etc.

Parameters:

• query: string - The CSS media query string (e.g. '(min-width: 768px)')

Returns:

• boolean - Whether the media query currently matches

Side effects:

• Adds a change listener on the MediaQueryList object
• Removes listener on unmount or query change

Example:

import { useMediaQuery } from 'react-essentials-functions';

function ResponsiveComponent() {
  const isMobile = useMediaQuery('(max-width: 767px)');
  const prefersDark = useMediaQuery('(prefers-color-scheme: dark)');
  const prefersReducedMotion = useMediaQuery('(prefers-reduced-motion: reduce)');

  return (
    <div>
      {isMobile ? <MobileLayout /> : <DesktopLayout />}
      {prefersDark && <span>Dark mode detected</span>}
    </div>
  );
}

Hook that returns the previous value of a variable. Useful for comparing current and previous props or state values.

Type Parameters:

• T - The type of the tracked value

Parameters:

• value: T - The value to track

Returns:

• T | undefined - The value from the previous render, or undefined on first render

Example:

import { usePrevious } from 'react-essentials-functions';
import { useState } from 'react';

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

  return (
    <div>
      <p>Current: {count}, Previous: {previousCount ?? 'N/A'}</p>
      <button onClick={() => setCount(count + 1)}>Increment</button>
    </div>
  );
}

Hook that provides a fetch function which automatically aborts previous requests and cleans up on unmount using AbortController. Prevents race conditions when multiple requests are made in sequence.

Parameters:

• None

Returns:

• (url: string, options?: RequestInit) => Promise<Response> - Fetch function with automatic abort handling

Side effects:

• Aborts the previous in-flight request when a new one is made
• Aborts any pending request on component unmount
• User-provided signal in options is ignored (the hook manages its own)

Example:

import { useSafeFetch } from 'react-essentials-functions';
import { useEffect } from 'react';

function DataComponent() {
  const safeFetch = useSafeFetch();

  useEffect(() => {
    const fetchData = async () => {
      try {
        const response = await safeFetch('https://api.example.com/data');
        const data = await response.json();
      } catch (error) {
        if (error.name !== 'AbortError') {
          console.error('Fetch error:', error);
        }
      }
    };

    fetchData();
  }, [safeFetch]);

  return <div>Loading data...</div>;
}

A version of useState that prevents state updates after the component unmounts, preventing memory leaks and "Can't perform a React state update on an unmounted component" warnings.

Type Parameters:

• T - The type of the state value

Parameters:

• initialValue: T | (() => T) - The initial state value

Returns:

• [T, (value: T | ((prevState: T) => T)) => void] - A tuple containing the current state and a safe setState function

Example:

import { useSafeState } from 'react-essentials-functions';
import { useEffect } from 'react';

function UserProfile({ userId }) {
  const [user, setUser] = useSafeState<User | null>(null);

  useEffect(() => {
    fetchUser(userId).then((data) => {
      // Safe even if component unmounted during fetch
      setUser(data);
    });
  }, [userId]);

  return user ? <div>{user.name}</div> : <div>Loading...</div>;
}

Hook to dynamically load external scripts with status tracking and callback support.

Parameters:

• url: string - The URL of the script to load
• options?: UseScriptOptions - Optional configuration:
  • onLoad?: () => void - Callback when script loads successfully
  • onError?: () => void - Callback when script fails to load
  • removeOnUnmount?: boolean - Whether to remove script on unmount (default: true)

Returns:

• UseScriptStatus - The current status: 'idle' | 'loading' | 'ready' | 'error'

Side effects:

• Appends a <script> tag to document.body
• Removes the script tag on unmount (unless removeOnUnmount: false)
• Detects and reuses already-loaded scripts

Example:

import { useScript } from 'react-essentials-functions';

function GoogleMapsComponent() {
  const status = useScript('https://maps.googleapis.com/maps/api/js', {
    onLoad: () => console.log('Google Maps loaded'),
    onError: () => console.error('Failed to load Google Maps'),
  });

  if (status === 'loading') return <div>Loading map...</div>;
  if (status === 'error') return <div>Error loading map</div>;
  if (status === 'idle') return <div>Initializing...</div>;

  return <div>Map is ready!</div>;
}

Hook to manage theme (light/dark) with localStorage persistence and SSR support. Automatically detects system color scheme preference via prefers-color-scheme when no theme has been previously stored.

Returns:

• [ThemeMode, () => void, boolean] - A tuple containing:
  • Current theme mode ('light' | 'dark')
  • Function to toggle between themes
  • Boolean indicating if component is mounted (useful for SSR)

Side effects:

• Reads/writes to localStorage with key 'theme'
• Detects system prefers-color-scheme preference on first load

Example:

import { useTheme } from 'react-essentials-functions';

function ThemeToggle() {
  const [theme, toggleTheme, mounted] = useTheme();

  // Avoid hydration mismatch
  if (!mounted) return null;

  return (
    <button onClick={toggleTheme}>
      Switch to {theme === 'light' ? 'dark' : 'light'} mode
    </button>
  );
}

Hook for managing a boolean toggle state. Provides a simple API for toggling, setting true, or setting false. Useful for modals, dropdowns, accordions, etc.

Parameters:

• initialValue?: boolean - The initial boolean value (default: false)

Returns:

• [boolean, () => void, () => void, () => void] - A tuple containing:
  • The current boolean value
  • toggle - Flips the value
  • setTrue - Sets to true
  • setFalse - Sets to false

Example:

import { useToggle } from 'react-essentials-functions';

function Modal() {
  const [isOpen, toggleOpen, open, close] = useToggle(false);

  return (
    <div>
      <button onClick={open}>Open Modal</button>
      {isOpen && (
        <div className="modal">
          <p>Modal content</p>
          <button onClick={close}>Close</button>
        </div>
      )}
    </div>
  );
}

Hook to get the current window dimensions with automatic updates on resize. SSR-safe (returns 0 for both dimensions when window is unavailable).

Returns:

• WindowDimensions - Object containing width and height of the window

Side effects:

• Adds a resize event listener on window
• Removes listener on unmount

Example:

import { useWindowDimensions } from 'react-essentials-functions';

function ResponsiveComponent() {
  const { width, height } = useWindowDimensions();

  return (
    <div>
      Window size: {width}px x {height}px
      {width < 768 ? <MobileLayout /> : <DesktopLayout />}
    </div>
  );
}

Component that conditionally wraps its children with a wrapper component based on a condition. When the condition is false, children are rendered unwrapped inside a fragment.

Props:

• condition: boolean - Whether to wrap the children
• wrapper: (children: React.ReactNode) => JSX.Element - Function that returns the wrapper element
• children: React.ReactNode - Children to wrap

Example:

import { ConditionalWrapper } from 'react-essentials-functions';

function LinkWrapper({ link, children }) {
  return (
    <ConditionalWrapper
      condition={!!link}
      wrapper={(c) => <a href={link}>{c}</a>}
    >
      <button>{children}</button>
    </ConditionalWrapper>
  );
}

This library is written in TypeScript and includes full type definitions. All types are exported for your convenience:

import type {
  Dimensions,
  WindowDimensions,
  ThemeMode,
  UseScriptStatus,
  UseScriptOptions,
  ConditionalWrapperProps,
} from 'react-essentials-functions';

MIT