curry is a function that returns function with first arguments pre-assigned to it. Arguments stored in closure

curry.js

Function.prototype.curry = function () {
    if (arguments.length<1) {
        return this;
    }
    var _this = this;
    var _args = Array.prototype.slice.call(arguments);
    return function() {
        return _this.apply(this, _args.concat(Array.prototype.slice.call(arguments)));
    }
}

//example usage
var add = function(a,b) { 
    return a+b; 
}

var add10 = add.curry(10)

add10(3) // 13