Question

I wand to check for the existence of a JavaScript method, when I have a variable with that method name inside it.

Using PHP I could do this:

$method = 'bar';
$object = new Foo;
if(method_exists($object, $method))
{
    //Foo->bar()
}

How can I do this in JavaScript? My first attempt failed:

var method = 'bar';
if(typeof(obj.method) != "undefined")
{
    obj.method();
}
else
{
    obj.default();
}

Answer 1

Check if the typeof the property is "function", using method as the key into the obj object:

((typeof obj[method] === "function") ? obj[method] : obj.default)();