/**

* @function upper

* @description Will convert the entire string to uppercase letters.

* @param {String} str - The input string

* @return {String} Uppercase string

* @example upper("hello") => HELLO

* @example upper("He_llo") => HE_LLO

*/

const upper = (str) => {

if (typeof str !== 'string') {

throw new TypeError('Argument should be string')

}

return str.replace(/[a-z]/g, (char) =>

String.fromCharCode(char.charCodeAt() - 32)

)

}

export default upper