bindMethod.js

// Binds a method to its owner, optionally adding more arguments
function bindMethod(_this, method) {
    method = _this[method];
    if (arguments.length <= 2) {
        return method.bind(_this);
    }
    var args = Array.prototype.slice.call(arguments, 2);
    return args.unshift(_this), method.bind.apply(method, args);
}

usage.js

function MyClass(value) {
    this.myMethod = function(param) {
        return value + (param || 0);
    }
}

v = 10;
m = new MyClass(v);
fn = bindMethod(m, 'myMethod');
fn() === v;

plus5 = bindMethod(m, 'myMethod', 5);
plus5 === v + 5;