How to write a test that checks for multiple types in chai

Question

I'm trying to write a test that would pass if the input is either a string or a null value

in chai is there something similar to

expect(foo).to.be.a('string').or.a('null')

If not what would be best practice when writing a test that needs to check for multiple types?

Answer 1

This would probably be the easiest way as there is no or keyword.

var str = null;

expect(str).to.satisfy(function(s){
    return s === null || typeof s == 'string'
});