Check if string contains only Number in javascript code example

Example 1: check if a string contains digits js

function hasNumber(myString) {
  return /\d/.test(myString);
}

Example 2: how to check if a string contains numbers in javascript

/**
 * Function to check if a string contains numbers
 * @author Okoro Redemption
 * @param {String} str - The string to be checked.
 * @returns {Boolean} str - The result of the check.
 */
function hasNumbers(str){
  var regexp = /d/g;
  return regexp.test(str);
};

// use function below
hasNumbers("I am 20years old"); // => true
hasNumbers("I am a boy"); // => false