Using substring() method in React

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Using substring() method in React

Author：JIYIK Last Updated：2025/03/16 Views：

Using the method in React substring():

Call the method on the string.
Pass the start and end index as parameters to it.
This method returns a new string containing only the specified portion of the original string.

const App = () => {
  const str = 'Walk the dog';

  const result = str.substring(0, 4);
  console.log(result); // 👉️ "Walk"

  return (
    <div>
      <h2>{result}</h2>
    </div>
  );
};

export default App;

The two parameters we pass to String.substringthe method are:

start index - the index of the first character to be included in the returned string
end index - up to but not including end index

JavaScriptThe indexes in are zero-based, which means the first index in the string is 0 and the last index is str.length - 1.

We can also use the method directly in JSX code substring.

const App = () => {
  const str = 'Walk the dog';

  return (
    <div>
      <h2>{str.substring(0, 4)}</h2>
    </div>
  );
};

export default App;

If we pass only the starting index to the method, it will return a new string containing the remaining characters.

const App = () => {
  const str = 'Walk the dog';

  const result = str.substring(5);
  console.log(result); // 👉️ "the dog"

  return (
    <div>
      <h2>{result}</h2>
    </div>
  );
};

export default App;

We start extracting characters from index 5 and continue till the end of the original string.

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