Regex: How to match a string that is not only numbers

Question

Is it possible to write a regular expression that matches all strings that does not only contain numbers? If we have these strings:

• abc

Answer 1

I am using /^[0-9]*$/gm in my JavaScript code to see if string is only numbers. If yes then it should fail otherwise it will return the string.

Below is working code snippet with test cases:

function isValidURL(string) {
  var res = string.match(/^[0-9]*$/gm);
  if (res == null)
    return string;
  else
    return "fail";
};

var testCase1 = "abc";
console.log(isValidURL(testCase1)); // abc

var testCase2 = "a4c";
console.log(isValidURL(testCase2)); // a4c

var testCase3 = "4bc";
console.log(isValidURL(testCase3)); // 4bc

var testCase4 = "ab4";
console.log(isValidURL(testCase4)); // ab4

var testCase5 = "123"; // fail here
console.log(isValidURL(testCase5));