Динамическая функция вызова

this.callFunction = this.call_function = function(name) {
    var args = Array.prototype.slice.call(arguments, 1);
    return window[name].call(this, ...args);
};

function sayHello(name, age) {
    console.log('hello ' + name + ', your\'e age is ' + age);
    return some;
}

console.log(call_function('sayHello', 'john', 30)); // hello john, your'e age is 30
Dead Dotterel