1.js

options.change && options.change();

2.js

if (options.change){ options.change(); }

// or

if ("change" in options) { options.change(); }

// or

if (Object.hasOwnProperty.call(options, "change")) { options.change(); }

// or ...

3.js

var options = {
  change: "foo"
};

4.js

if (_.isFunction(options.change)){ 
  options.change(); 
}

5.js

// explicit separation of options and options persistence
function doStuff(options, optionsPersistence){
  options.set("something", "that value");
  options.set("whatever", 1234.1234);
  
  // assume the save method is there, because that's what
  // the API "contract" or "protocol" says should be there
  if (optionsPersistence) {
    optionsPersistence.save(options);
  }
}