问原型继承: Object.create与Object.assign

EN

      function Foo(name) {
        this.name = name;
      }
      
      Foo.prototype.myName = function () {
        return this.name;
      };
      
      function Bar(name, label) {
        Foo.call(this, name);
        this.label = label;
      }
      
      // here, we make a new `Bar.prototype`
      // linked to `Foo.prototype`
      Bar.prototype = Object.create(Foo.prototype);
      
      // Beware! Now `Bar.prototype.constructor` is gone,
      // and might need to be manually "fixed" if you're
      // in the habit of relying on such properties!
      
      Bar.prototype.myLabel = function () {
        return this.label;
      };
      
      var a = new Bar("a", "obj a");
      
      console.log(a.myName()); // "a"
      console.log(a.myLabel()); // "obj a"