curry.js

Function.prototype.curry = function() {
    if (arguments.length < 1) {
        return this;
    }

    const self = this;
    const args = toArray(arguments);

    return function() {
        return self.apply(this, args.concat(toArray(arguments)));
    }
}

function toArray(args) {
    return Array.prototype.slice.call(args);
}