Function cleanTelephone

Cleans a telephone string by removing any non-numeric characters.

This function takes a telephone number as a string and returns a new string that contains only the numeric characters (0-9) and the plus sign (+) at the beginning, if present. All other characters are stripped away.

Example

const rawTelephone = '+0 (123) 456-7890';
const cleanedTelephone = cleanTelephone(rawTelephone);
console.log(cleanedTelephone); // Outputs: '+01234567890'