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How to change the first letter of variable to upper case with JavaScript?

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Sometimes, we want to change the first letter of variable to upper case with JavaScript.

In this article, we’ll look at how to change the first letter of variable to upper case with JavaScript.

How to change the first letter of variable to upper case with JavaScript?

To change the first letter of variable to upper case with JavaScript, we can use the string replace method.

For instance, we write

const str = "hello world";
const newStr = str.toLowerCase().replace(/\b[a-z]/g, (letter) => {
  return letter.toUpperCase();
});

to call str.toLowerCase to convert all the letters in str to lower case.

Then we call replace with a regex that gets the first letter of each word.

\b means word boundary, so we get the first lower case letter of each word.

We use the g flag to get all matches.

Then we replace them all with upper case letter by using a function that returns letter.toUpperCase where letter is the match being replaced.

Conclusion

To change the first letter of variable to upper case with JavaScript, we can use the string replace method.

By John Au-Yeung

Web developer specializing in React, Vue, and front end development.

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