问如何继承javascript函数？

EN

// Don't break the function prototype.
// pd - https://github.com/Raynos/pd
var proto = Object.create(Function.prototype, pd({
  "prop": 42
}));

var f = function() { return "is a function"; };
f.__proto__ = proto;

console.log(f.hasOwnProperty("prop")); // false
console.log(f.prop); // 42
console.log(f()); // "is a function"

var finherit = function (parent, child) {
    var f = function() { 
        parent.apply(this, arguments);
        child.apply(this, arguments);
    };
    f.__proto__ = parent;
    Object.keys(child).forEach(function _copy(key) {
        f[key] = child[key];
    });
    return f;
};

/*
  Creates a new function whose prototype is proto.
  The function body is the same as the function fbody.
  The hash of propertydescriptors props is passed to defineproperties just like
  Object.create does.
*/
Function.create = (function() {
  var functionBody = function _getFunctionBody(f) {
    return f.toString().replace(/.+\{/, "").replace(/\}$/, "");
  };
  var letters = "abcdefghijklmnopqrstuvwxyz".split("");

  return function _create(proto, fbody, props) {
    var parameters = letters.slice(0, fbody.length);
    parameters.push(functionBody(fbody));
    var f = Function.apply(this, parameters);
    f.__proto__ = proto;
    Object.defineProperties(f, props);
    return f;
  };
})();

var f1 = function () {
  console.log("do things");
};

f1.method = function() { return 42; };

var f2 = f1 <| function () {
  super();
  console.log("do more things");
}
console.log(f1.isPrototypeOf(f2)); // true
console.log(f2()); // do things do more things
console.log(f2.hasOwnProperty("method")); // false
console.log(f2.method()); // 42