Matching exact string with JavaScript

Question

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 

Answer 1

Either modify the pattern beforehand so that it only matches the entire string:

var r = /^a$/ 

or check afterward whether the pattern matched the whole string:

function matchExact(r, str) {    var match = str.match(r);    return match && str === match[0]; } 

Answer 2

Write your regex differently:

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