Add arguments in a virtual getter
Add it as an instance method instead of a virtual getter.
schema.methods.getSomething = function(what) { if (!what) { return this.somethingElse } else { return this.something[what] }};
Getters don't accept any arguments, because they are supposed to replace normal "get attribute" functionality, without brackets. So what you are need is to define a method:
Schema.methods.getSomething = function(what) { if (!what) { return this.somethingElse; } else { return this.something[what]; }};and then you can simply call:
mySchemaObject.getSomething( "test" );