How to Capitalize first letter of String in JavaScript

Needing to capitalize the first letter of a string is a common task in JavaScript.

Thankfully, there are many ways to do this, some methods better than others.

In this post, we'll learn how to capitalize the first letter of a string.

Capitalizing the first letter of a string

The most simple way to accomplish this is to use a combination of the charAt() and toUpperCase() methods.

We use the charAt() method to get the first letter of a string, then we use the toUpperCase() method to capitalize it.

That looks like this:

JAVASCRIPT
const string = "hello world";
const firstLetter = string.charAt(0);
const capitalizedFirstLetter = firstLetter.toUpperCase(); // "H"

Great, now that we've been able to capitalize the first letter of a string, we just need to add it to the rest of the string.

You can get the rest of the string by using the slice() method.

JAVASCRIPT
const string = "hello world";
const restOfString = string.slice(1); // "ello world"

Now that we can get the first letter capitalized and the rest of the string, we can combine them together.

JAVASCRIPT
const string = "hello world";
const firstLetter = string.charAt(0);
const capitalizedFirstLetter = firstLetter.toUpperCase(); // "H"
const restOfString = string.slice(1); // "ello world"
const capitalizedString = capitalizedFirstLetter + restOfString; // "Hello world"

Thankfully, we can simply this greatly into a one-liner

JAVASCRIPT
const string = "hello world";
const capitalizedString = string.charAt(0).toUpperCase() + string.slice(1); // "Hello world"

We can also turn this into a function for reusability.

JAVASCRIPT
const capitalize = string => string.charAt(0).toUpperCase() + string.slice(1);

const capitalizedString = capitalize("hello world"); // "Hello world"

Conclusion

In this post, we learned how to capitalize the first letter of a string.

We were able to accomplish this using a combination of the charAt() and toUpperCase() methods, and we wrote a standalone function for reusability.

Hope you've found this content helpful. Thanks for reading!

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