yup validation to allow only numbers in javascript code example

Example: yup phone validation

const phoneRegExp = /^((\\+[1-9]{1,4}[ \\-]*)|(\\([0-9]{2,3}\\)[ \\-]*)|([0-9]{2,4})[ \\-]*)*?[0-9]{3,4}?[ \\-]*[0-9]{3,4}?$/

phoneNumber: Yup.string().matches(phoneRegExp, 'Phone number is not valid')