rrr.js

// Manually simulating an apply() for constructors

var arr = [2011, 11, 24];
new (Function.prototype.bind.apply(
         Date, [null].concat(arr)))


// Switching over an object’s constructor

try {
    ...
} catch (e) {
    switch (e.constructor) {
        case SyntaxError:
            ...
            break;
        case CustomError:
            ...
            break;
        ...
    }
}