function addOneOf(name, message, method) {
    Assertion.add(name, function(vals) {
      if (arguments.length !== 1) {
        vals = Array.prototype.slice.call(arguments);
      } else {
        should(vals).be.Array();
      }

      this.params = { operator: message, expected: vals };

      var obj = this.obj;
      var found = false;

      forEach(vals, function(val) {
        try {
          should(val)[method](obj);
          found = true;
          return false;
        } catch (e) {
          if (e instanceof should.AssertionError) {
            return; //do nothing
          }
          throw e;
        }
      });

      this.assert(found);
    });
  }
Exact comparison using ===.

@name equal
@memberOf Assertion
@category assertion equality
@alias Assertion#equals
@alias Assertion#exactly
@param {*} val Expected value
@param {string} [description] Optional message
@example

10.should.be.equal(10);
'a'.should.be.exactly('a');

should(null).be.exactly(null);