Textarea with character limit

OSCC · React, Components, State, Callback, Event · Oct 13, 2021

Renders a textarea component with a character limit.

  • Use the useState() hook to create the content state variable. Set its value to that of value prop, trimmed down to limit characters.
  • Create a method setFormattedContent, which trims the content down to limit characters and memoize it, using the useCallback() hook.
  • Bind the onChange event of the <textarea> to call setFormattedContent with the value of the fired event.
const LimitedTextarea = ({ rows, cols, value, limit }) => {
  const [content, setContent] = React.useState(value.slice(0, limit));

  const setFormattedContent = React.useCallback(
    text => {
      setContent(text.slice(0, limit));
    },
    [limit, setContent]
  );

  return (
    <>
      <textarea
        rows={rows}
        cols={cols}
        onChange={event => setFormattedContent(event.target.value)}
        value={content}
      />
      <p>
        {content.length}/{limit}
      </p>
    </>
  );
};
ReactDOM.render(
  <LimitedTextarea limit={32} value="Hello!" />,
  document.getElementById('root')
);

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