To convert uppercase in javascript

How to Convert a String to Uppercase in JavaScript?

In this blog, we will explore the world of string transformations in JavaScript with this comprehensive blog. Learn multiple methods, such as using built-in functions like toUpperCase(), leveraging regular expressions with replace(), harnessing the power of the Intl object, and creating custom implementations.

Introduction:

JavaScript is a versatile programming language used extensively in web development. One common task developers encounter is converting strings to uppercase. Whether you want to normalize user input or manipulate text data, knowing how to convert strings to uppercase is an essential skill. In this blog, we will explore multiple methods to achieve this conversion, along with their advantages and use cases. By the end, you’ll have a comprehensive understanding of various techniques to capitalize strings in JavaScript.

Method 1: Using the toUpperCase() Method

The toUpperCase() method is a built-in JavaScript function that converts a string to uppercase. It provides a straightforward and concise solution for uppercase conversion. Here’s an example program:

const originalString = "hello, world!"; const uppercaseString = originalString.toUpperCase(); console.log(uppercaseString); 

Output:

In this method, we utilize the toUpperCase() method, which converts all characters in the string to uppercase. The originalString variable contains the input string, while the uppercaseString variable stores the converted string. Finally, the console.log() function displays the converted string.

Method 2: Using String.prototype.replace() with a Regular Expression

Another approach to converting strings to uppercase in JavaScript involves using the replace() method in conjunction with a regular expression. Let’s take a look at an example:

const originalString = "hello, world!"; const uppercaseString = originalString.replace(/[a-z]/g, (match) => match.toUpperCase()); console.log(uppercaseString); 

Output:

In this method, we use the replace() method with a regular expression pattern ( /[a-z]/g ) to match all lowercase letters in the string. The second argument of replace() is a callback function that takes the matched substring as an argument and returns its uppercase equivalent using the toUpperCase() method. This approach allows for more fine-grained control over the conversion process.

Method 3: Using the Intl object

Introduced in ECMAScript 2015 (ES6), the Intl object provides language-sensitive string comparison, number formatting, and case mapping. We can leverage the toLocaleUpperCase() method from this object to convert strings to uppercase:

const originalString = "hello, world!"; const uppercaseString = originalString.toLocaleUpperCase(); console.log(uppercaseString); 

Output:

The toLocaleUpperCase() method of the Intl object converts the string to uppercase based on the rules of the language and locale specified by the user’s environment. This method is particularly useful when dealing with multilingual applications or when precise localization is required.

Method 4: Custom Implementation

If you prefer a more customized approach, you can create your own function to convert strings to uppercase. This allows for greater flexibility and control over the conversion logic. Here’s an example:

function convertToUppercase(string) < let uppercaseString = ""; for (let i = 0; i < string.length; i++) < const char = string[i]; const uppercaseChar = char.toUpperCase(); uppercaseString += uppercaseChar; >return uppercaseString; > const originalString = "hello, world!"; const uppercaseString = convertToUppercase(originalString); console.log(uppercaseString); 

Output:

In this custom implementation, we define a convertToUppercase() function that takes a string as input. Using a for loop, we iterate over each character in the string and convert it to uppercase using the toUpperCase() method. The uppercase characters are then appended to the uppercaseString variable. Finally, the function returns the converted string.

Conclusion:

In this comprehensive guide, we explored multiple methods to convert strings to uppercase in JavaScript. We covered the built-in toUpperCase() method, using replace() with a regular expression, leveraging the Intl object, and creating a custom implementation. Each method has its own advantages and can be used based on specific requirements. By understanding these techniques, you’ll be well-equipped to handle string uppercase conversions in your JavaScript projects.

Related Post

Источник

String.prototype.toUpperCase()

The toUpperCase() method returns the calling string value converted to uppercase (the value will be converted to a string if it isn’t one).

Try it

Syntax

Return value

A new string representing the calling string converted to upper case.

Description

The toUpperCase() method returns the value of the string converted to uppercase. This method does not affect the value of the string itself since JavaScript strings are immutable.

Examples

Basic usage

.log("alphabet".toUpperCase()); // 'ALPHABET' 

Conversion of non-string this values to strings

This method will convert any non-string value to a string, when you set its this to a value that is not a string:

const a = String.prototype.toUpperCase.call( toString()  return "abcdef"; >, >); const b = String.prototype.toUpperCase.call(true); // prints out 'ABCDEF TRUE'. console.log(a, b); 

Specifications

Browser compatibility

BCD tables only load in the browser

See also

Found a content problem with this page?

This page was last modified on Apr 6, 2023 by MDN contributors.

Your blueprint for a better internet.

MDN

Support

Our communities

Developers

Visit Mozilla Corporation’s not-for-profit parent, the Mozilla Foundation.
Portions of this content are ©1998– 2023 by individual mozilla.org contributors. Content available under a Creative Commons license.

Источник

JavaScript String toUpperCase()

The toUpperCase() method converts a string to uppercase letters.

The toUpperCase() method does not change the original string.

See Also:

Syntax

Parameters

Return Value

Related Pages

Browser Support

toUpperCase() is an ECMAScript1 (ES1) feature.

ES1 (JavaScript 1997) is fully supported in all browsers:

Chrome	Edge	Firefox	Safari	Opera	IE
Yes	Yes	Yes	Yes	Yes	Yes

COLOR PICKER

Report Error

If you want to report an error, or if you want to make a suggestion, do not hesitate to send us an e-mail:

Thank You For Helping Us!

Your message has been sent to W3Schools.

Top Tutorials

Top References

Top Examples

Get Certified

W3Schools is optimized for learning and training. Examples might be simplified to improve reading and learning. Tutorials, references, and examples are constantly reviewed to avoid errors, but we cannot warrant full correctness of all content. While using W3Schools, you agree to have read and accepted our terms of use, cookie and privacy policy.

Источник

JavaScript Uppercase – How to Capitalize a String in JS with .toUpperCase

Kolade Chris

While working with strings in JavaScript, you can perform different operations on them.

The operations you might perform on strings include capitalization, conversion to lowercase, adding symbols within words, and many more.

In this article, I will show you how to convert a string to uppercase letters with the .toUpperCase() string method.

Basic Syntax of the .toUpperCase() Method

To use the .toUpperCase() method, assign the string you want to change to uppercase to a variable and then prepend it with .toUpperCase() .

How to Capitalize a String with .toUpperCase

As already stated, you can assign a string to a variable and then use the .toUpperCase() method to capitalize it

const name = "freeCodeCamp"; const uppercase = name.toUpperCase(); console.log(uppercase); // Output: FREECODECAMP 

You can also write a function and return .toUpperCase() in it, so a stated parameter will be capitalized when the function is called.

function changeToUpperCase(founder) < return founder.toUpperCase(); >// calling the function const result = changeToUpperCase("Quincy Larson"); // printing the result to the console console.log(result); // Output: QUINCY LARSON 

In the script above:

• I defined a function named changeToUpperCase with a placeholder of founder
• with the return statement inside the function, I told the function that what I want it to do is to change to uppercase letters any parameter I specify when I call it
• I then assigned the function call — changeToUpperCase to a variable named result
• with the help of the variable, I was able to print the result of the function to the console

Conclusion

You can use the .toUpperCase() method, fully known as String.prototype.toUpperCase() , when you need to capitalize strings in your JavaScript projects.

If you find this article helpful, please share it with your friends and family.

Kolade Chris

Web developer and technical writer focusing on frontend technologies. I also dabble in a lot of other technologies.

If you read this far, tweet to the author to show them you care. Tweet a thanks

Learn to code for free. freeCodeCamp’s open source curriculum has helped more than 40,000 people get jobs as developers. Get started

freeCodeCamp is a donor-supported tax-exempt 501(c)(3) charity organization (United States Federal Tax Identification Number: 82-0779546)

Our mission: to help people learn to code for free. We accomplish this by creating thousands of videos, articles, and interactive coding lessons — all freely available to the public. We also have thousands of freeCodeCamp study groups around the world.

Donations to freeCodeCamp go toward our education initiatives, and help pay for servers, services, and staff.

Источник