JavaScript String.toLocaleUpperCase() Method

1. Syntax of JavaScript string.toLocaleUpperCase():
2. Example Codes: Use the String.toLocaleUpperCase() Method to Convert the Characters to Uppercase
3. Example Codes: Use the string.toLocaleUpperCase() Method to Specify a Language Tag as a locale Parameter

The string.toLocaleUpperCase() method converts the lowercase characters of a given string into uppercase based on the specified locale case mappings. By default, the method will use the current locale of the host.

For most languages, there is no need to add a parameter in the toLocaleUpperCase() method.

Syntax of JavaScript string.toLocaleUpperCase():

refString.toLocaleUpperCase();
refString.toLocaleUpperCase(locale);

Parameter

Return

It returns a new string that includes all the characters of a string in uppercase based on particular locale case mappings.

Example Codes: Use the String.toLocaleUpperCase() Method to Convert the Characters to Uppercase

The string.toLocaleUpperCase() method converts a string in lowercase characters into uppercase. Some languages might require a locale parameter in the string.toLocaleUpperCase() method to convert lowercase into uppercase characters.

To check the output, we have passed the string.toLocaleUpperCase() method without any parameter in the following example.

let string = 'café';
let upStr = string.toLocaleUpperCase();
console.log(upStr);

Output:

 CAFÉ

Example Codes: Use the string.toLocaleUpperCase() Method to Specify a Language Tag as a locale Parameter

The websites and applications run on different hosts and browsers. Using the BCF 47 language tags as a parameter in the string.toLocaleUpperCase() method, we can ensure that the string containing lowercase characters is accurately converted into uppercase.

We have passed a language tag as a locale parameter in the example below.

var string = 'select français or español language.';
let frStr = string.toLocaleUpperCase('fr-FR');
console.log(frStr);

Output:

SELECT FRANÇAIS OR ESPAÑOL LANGUAGE.

The string.toLocaleUpperCase() method converts a string containing local language characters into uppercase based on the specific locale case mappings. Since, by default, this method uses the host’s current locale, we add language tags as a parameter.

The .toUpperCase() method gives similar results; however, the toLocaleUpperCase() method converts locale languages with accuracy.