console 命令行工具 X clear

console

function extend(sup, base) {
  var descriptor = Object.getOwnPropertyDescriptor(
    base.prototype, 'constructor'
  );
  base.prototype = Object.create(sup.prototype);
  var handler = {
    construct: function(target, args) {
      var obj = Object.create(base.prototype);
      this.apply(target, obj, args);
      return obj;
    },
    apply: function(target, that, args) {
      sup.apply(that, args);
      base.apply(that, args);
    }
  };
  var proxy = new Proxy(base, handler);
  descriptor.value = proxy;
  Object.defineProperty(base.prototype, 'constructor', descriptor);
  return proxy;
}

var Person = function(name) {
  this.name = name;
};

var Boy = extend(Person, function(name, age) {
  this.age = age;
});

Boy.prototype.gender = 'M';

var Peter = new Boy('Peter', 13);

console.log(Peter.gender);  // "M"
console.log(Peter.name);    // "Peter"
console.log(Peter.age);     // 13

<!DOCTYPE html>
<html>
<body>
    Proxy: 拓展constructor
</body>
</html>