constantCase 
Converts a string to constant case.
Constant case is a naming convention where each word is written in uppercase letters and separated by an underscore (_). For example, CONSTANT_CASE.
Signature 
typescript
function constantCase(str: string): string;Parameters 
- str(- string): The string that is to be changed to constant case.
Returns 
(string): The converted string to constant case.
Examples 
typescript
const convertedStr1 = constantCase('camelCase'); // returns 'CAMEL_CASE'
const convertedStr2 = constantCase('some whitespace'); // returns 'SOME_WHITESPACE'
const convertedStr3 = constantCase('hyphen-text'); // returns 'HYPHEN_TEXT'
const convertedStr4 = constantCase('HTTPRequest'); // returns 'HTTP_REQUEST'
