One-shot setters

os_setter.js

// One-shot set function
function error (fn)
{
    // Create locally bound copy of `fn`
    var handle = fn.bind(this);
    
    // Overwrite function
    error = handle;
}

// Set the error handling function
error(function () {
    console.log('An error occured.');
});

try {
    undef('This throws.');
} catch (e) {
    error();
}