You have to use charAt(), toUpperCase(), and slice() method to capitalize the first letter in JavaScript. The charAt() function returns the character at a given position in a string.
str.charAt(0).toUpperCase() + str.slice(1);And toUpperCase() function converts all the characters of an input string to uppercase, where slices a given string from a specified “start” position until the specified “end” position.
JavaScript capitalize first letter
Simple example code.
Using String Methods:
<!DOCTYPE html>
<html>
<body>
<script>
const str = 'abc efg';
const res = str.charAt(0).toUpperCase() + str.slice(1);
console.log(res);
</script>
</body>
</html> Output:
Using ES6 Arrow Function and Template Literals:
You can also use ES6 features like arrow functions and template literals for a concise solution:
const capitalizeFirstLetter = (inputString) =>
`${inputString.charAt(0).toUpperCase()}${inputString.slice(1)}`;
const originalString = "hello world";
const capitalizedString = capitalizeFirstLetter(originalString);
console.log(capitalizedString); // "Hello world"
Using Regular Expression:
Another way to capitalize the first letter is by using a regular expression:
function capitalizeFirstLetter(inputString) {
return inputString.replace(/^\w/, (char) => char.toUpperCase());
}
const originalString = "hello world";
const capitalizedString = capitalizeFirstLetter(originalString);
console.log(capitalizedString); // "Hello world"
How do I make the first letter of a string uppercase in JavaScript?
Answer: "this is a test" → "This is a test"
The basic solution is:
function capitalizeFirstLetter(string) {
return string.charAt(0).toUpperCase() + string.slice(1);
}
console.log(capitalizeFirstLetter('foo')); // FooComment if you have any doubts or suggestions on this JS basic topic.
Note: The All JS Examples codes are tested on the Firefox browser and the Chrome browser.
OS: Windows 10
Code: HTML 5 Version