Slash resolves to wrong path

[bbarni]

test("joins slash in path", () => {
  assert.equal(urlJoin("/foo", "/", "bar", "?test=123"), "/foo/bar?test=123");
});

✖ joins slash in path (0.999819ms)
AssertionError [ERR_ASSERTION]: Expected values to be strictly equal:

• actual - expected

• '/foo//bar?test=123'

• '/foo/bar?test=123'
  ^