How do you import a javascript package from a cdn/script tag in React?

javascript

prompt-engineering

useeffect

typescript

byNikita Barsukov·Feb 14, 2025

Rapidly import a JS library in React by inserting its CDN’s <script> tag within public/index.html:

<script src="https://cdn.example.com/library.min.js"></script>

Subsequently, employ the library’s global variable in your React files:

const MyComponent = () => {
  console.log(LibraryGlobal.someMethod());  // Replace 'LibraryGlobal' with actual global variable name
};

Furthermore, confirm that the library’s entirely loaded before utilizing it, perhaps through a condition or state in your component.

Lifehack: Dynamically managing external scripts in React

From dynamic content loading to state management, React is all about being reactive. Stick your <script> tag dynamically into your React app using the handy dandy useEffect hook:

/// Because managing scripts dynamically is too mainstream!
useEffect(() => {
  const script = document.createElement('script');
  script.src = 'https://cdn.example.com/library.min.js';
  script.async = true;

  document.body.appendChild(script);

  // Clean up after ourselves, like a well-behaved app should!
  return () => {
    document.body.removeChild(script);
  };
}, []);

Whoever told TypeScript that everything is typed, forgot to tell the window object. Oh well! Let's remind it, shall we?

declare global {
  interface Window {
    LibraryGlobal: any;  // Our friendly library object hitching a ride on the infamous `window`
  }
}
console.log(window.LibraryGlobal.someMethod());

Or let's just live life on the edge (Not recommended for production. Remember, with great power comes great responsibility):

console.log((window as any).LibraryGlobal.someMethod());

A bit too much for comfort? Chill! Meet react-helmet, your one-stop solution to managing external scripts effortlessly:

<Helmet>
  <script src="https://cdn.example.com/library.min.js" type="text/javascript" />
</Helmet>

Being a grown-up React app: Handling loading states

Show off your React prowess by intelligently handling the loading status of your external scripts. It's like your app saying, "I got this, don't you worry!".

Safety first: The flip side of using external scripts

Sure, external CDs are convenient, but with convenience comes responsibility! Security and stability primaries, remember? Try hosting the script on your own server to keep things under check.

'Automagically' handling script loads with React Helmet

Even magic needs a spell. For us, the spell is onChangeClientState:

<Helmet onChangeClientState={(newState, addedTags) => {
  if (addedTags && addedTags.scriptTags) {
    const scriptTag = addedTags.scriptTags.find(s => s.src === 'https://cdn.example.com/library.min.js');
    if (scriptTag) {
      scriptTag.onload = () => console.log('Library loaded. Time to conjure magic!');
    }
  }
}}>
  <script src="https://cdn.example.com/library.min.js" type="text/javascript" />
</Helmet>

TypeScript: Your guardian angel

Strong typing, goodbye runtime errors! Keep your app bug-free by leveraging TypeScript’s stellar type safety:

interface LibraryGlobal {
  someMethod: () => ReturnType;
}

const handleWithCare: LibraryGlobal = (window as any).LibraryGlobal;
console.log(handleWithCare.someMethod());

The importance of error handling

When life gives you lemons, make lemonade. Ensure your application robustly handles potential loading issues with dynamic script tags:

const [isLoaded, setIsLoaded] = useState(false);
const [isError, setIsError] = useState(false);

useEffect(() => {
  const script = document.createElement('script');
  script.src = "https://cdn.example.com/library.min.js";
  script.onload = () => setIsLoaded(true);
  script.onerror = () => setIsError(true);

  document.body.appendChild(script);

  return () => {
    document.body.removeChild(script);
  };
}, []);

if (isError) {
  // Implement fallback or notify user
}