toUpperCase

The toUpperCase() method returns a new string with all characters in uppercase.

Interactive example

Syntax

function toUpperCase<
	GenericInput extends string
>(
	input: GenericInput
): Uppercase<GenericInput>;

Parameters

• input: The string to modify. The type is generic (GenericInput extends string) to allow precise literal type inference.

Return value

A new string with all characters in uppercase. The return type is precisely inferred thanks to TypeScript's Uppercase<GenericInput> utility type.

See also

• toLowerCase: Converts the entire string to lowercase.
• capitalize: Uppercases the first letter of a string.
• normalize: Normalizes a Unicode string according to a specific form.

Sources

• MDN Web Docs - String.prototype.toUpperCase()
• TypeScript - Uppercase<StringType> - TypeScript utility type for type inference