When a falsy check against undefined returns a ReferenceError in JavaScript...

...something like this will bubble up to the console...

Uncaught ReferenceError: foo is not defined

 
 

...and something like this is a better way to deal with the falsy check:

if (typeof myThing != "undefined") {
   myThing.useMyMethod(true);
}

 
 

Interesting links to do with the same subject matter:

• http://stackoverflow.com/questions/8568332/uncaught-referenceerrorfoobar-is-not-defined-anonymous-function
• http://stackoverflow.com/questions/9981104/why-does-an-undefined-variable-in-javascript-sometimes-evaluate-to-false-and-som