useTypewriter

A hook that simulates typing of a string.

Usage

tsx
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import useTypewriter from "@/hooks/use-typewriter";

export default function Example() {
  const value = useTypewriter("Hello, world!", 2000);

  return <div>{value}</div>;
}

Installation

bash
npx shadcn add "https://registry.niels.foo/use-typewriter.json"

Source

tsx

import { useEffect, useState } from "react";

export default function useTypewriter(text: string, speed = 50) {
  const [value, setValue] = useState("");

  /**
   * In a short interval add a letter to mimic typing of the placeholder
   */
  useEffect(() => {
    const interval: NodeJS.Timeout = setInterval(() => {
      if (value === text) {
        clearInterval(interval);
        return;
      }

      // Server revalidated with a different string, so don't bother continuing the current typewriter
      if (!text.startsWith(value)) {
        return clearInterval(interval);
      }

      // Add the next letter
      const updated = value + text[value.length];
      setValue(updated);
    }, speed);

    return () => clearInterval(interval);
  });

  return value;
}