React introduced useTransition as one of its concurrent features to enhance performance when dealing with state updates that may cause UI delays. This article will show how useTransition works and demonstrate how to use it effectively with TypeScript.

🚀 What is useTransition?

useTransition is a built-in React Hook that allows you to mark certain state updates as non-blocking, ensuring a smoother UI experience.

This is particularly useful for optimizing user interactions where updates might be computationally expensive or cause noticeable UI lag.

⚡ Why Use useTransition?

  • Prevents UI blocking during expensive state updates.

  • Enhances performance by prioritizing urgent updates over transitions.

  • Provides a built-in mechanism for tracking pending transitions.

🛠️ Syntax of useTransition

The useTransition hook returns a tuple containing:

  • A boolean (isPending) that indicates whether a transition is in progress.

  • A function (startTransition) that wraps non-urgent updates.

const [isPending, startTransition] = useTransition();

🔥 Practical Example with TypeScript

Let's say we have a search input that filters a large dataset. Instead of updating the UI immediately (which can cause lag), we use useTransition to mark the filtering operation as a low-priority update.

import React, { useState, useTransition } from "react";

const LargeListFilter: React.FC = () => {
  const [query, setQuery] = useState("");
  const [filteredData, setFilteredData] = useState<string[]>([]);
  const [isPending, startTransition] = useTransition();

  const data = Array.from({ length: 10000 }, (_, i) => `Item ${i + 1}`);

  const handleSearch = (event: React.ChangeEvent<HTMLInputElement>) => {
    setQuery(event.target.value);
    startTransition(() => {
      setFilteredData(
        data.filter((item) => item.toLowerCase().includes(event.target.value.toLowerCase()))
      );
    });
  };

  return (
    <div>
      <input
        type="text"
        value={query}
        onChange={handleSearch}
        placeholder="Search items..."
      />
      {isPending && <p>Loading...p>}
      <ul>
        {filteredData.map((item) => (
          <li key={item}>{item}li>
        ))}
      ul>
    div>
  );
};

export default LargeListFilter;

🎯 Key Takeaways

  1. Optimized Performance: useTransition ensures that the UI remains responsive while performing expensive operations.

  2. Improved User Experience: Users don’t experience noticeable UI freezes when interacting with the app.

  3. Simple API: With just two values (isPending and startTransition), you can manage UI responsiveness effectively.

⚡ When to Use useTransition

  • Filtering/searching large datasets.

  • Rendering heavy UI components.

  • Fetching and displaying large amounts of data.

  • Any scenario where UI blocking due to state updates needs to be minimized.

🎯 Conclusion

The useTransition hook is a powerful tool in React’s concurrent rendering model that helps prevent UI blocking while handling complex state updates. Using it with TypeScript ensures type safety and a better development experience.

By integrating useTransition, you can create smoother, more responsive applications that prioritize user experience. 🚀

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