How to make first letter of a string uppercase in JavaScript ?
Last Updated :
28 Nov, 2023
There are a number of ways to capitalize the first letter of the string in JavaScript.
Here are some common approaches to make the first letter of a string uppercase in JavaScript:
JavaScript toUpperCase() Function: This function applies on a string and changes all letters to uppercase.
This function applies to a string and slices it according to the passed parameter.
Syntax:
string.slice(start, end)
Example: This example uses the slice() method to convert the first letter to uppercase.
Javascript
function capitalizeFLetter() {
let string = 'geeksforgeeks' ;
console.log(string[0].toUpperCase() +
string.slice(1));
}
capitalizeFLetter()
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This charAt() function returns the character at a given position in the string.
Syntax:
string.charAt(index)
Example: This example uses charAT() method to make the first letter of a string uppercase.
Javascript
function capitalizeFLetter() {
let string = 'geeksforgeeks' ;
console.log(string.charAt(0).toUpperCase() +
string.slice(1));
}
capitalizeFLetter()
|
This is a built-in function in JavaScript that is used to replace a slice of a string with another string or a regular expression. The original string will not be affected.
Syntax:
str.replace(A, B)
The below examples show the conversion to uppercase using the above-described methods.
Example: This example uses string.replace() method to make the first letter of a string uppercase.
Javascript
function capitalizeFLetter() {
let string = 'geeksforgeeks' ;
console.log(string.replace(/^./, string[0].toUpperCase()));
}
capitalizeFLetter()
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Approach 4 : Using the split() , map() and join() methods
The split() method divides the string into an array of characters, map() converts the first character to uppercase, and join() merges the modified array into a string.
Example: In this example, w are using the above-explained approach.
Javascript
let str = "geeksforgeeks" ;
let result = str.split( '' ).map((char, index) =>
index === 0 ? char.toUpperCase() : char).join( '' );
console.log(result);
|
Approach 5 : Using ES6 spread syntax and join() method
The spread syntax converts the string into an array, the map() method transforms the first character to uppercase, and join() merges the modified array into a string.
Syntax:
let result = [...str][0].toUpperCase() + [...str].slice(1).join('');
Example: In this example, we are using the above-explained approach.
Javascript
let str = "geeksforgeeks" ;
let result = [...str].map((char, index) =>
index === 0 ? char.toUpperCase() : char).join( '' );
console.log(result);
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In this approach we are using an immediately-invoked arrow function to capitalize the first letter of the string “geeksforgeeks” and concatenate it with the remaining characters, resulting in the string “Geeksforgeeks”.
Syntax:
const result = (() => {
const firstChar = str.charAt(0).toUpperCase();
const remainingChars = str.slice(1);
return `${firstChar}${remainingChars}`;
})();
Example: In this example, ES6 arrow functions and template literals to succinctly transform the first letter of the string to uppercase using the replace() method.
Javascript
const str = "geeksforgeeks" ;
const result = (() => {
const firstChar = str.charAt(0).toUpperCase();
const remainingChars = str.slice(1);
return `${firstChar}${remainingChars}`;
})();
console.log(result);
|
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