Matching exact string with javascript

How can I test if a regex matches a string exactly?

var r = /a/;
r.test("a"); // returns true
r.test("ba"); // returns true
testExact(r, "ba"); // should return false
testExact(r, "a"); // should return true

From stackoverflow

• either

  var r = /^.$/
  

  or

  function matchExact(r, str) { 
     return str === str.match(r);
  }
  

• Write your regex differently:

  var r = /^a$/;
  r.test('a'); // true
  r.test('ba'); // false
  

• If you do not use any placeholders (as the "exactly" seems to imply), how about string comparison instead?

  If you do use placeholders, ^ and $ match the beginning and the end of a string, respectively.