old_contents: export default function decorators() {
    console.group('ES-next: Stage-2: decorators');
    {
      console.log(`
        class Hoge {
          @decorator
          instance = 1;
  
          @decorator
          method() {
            console.log('Hoge.prototype.method()');
          }
        }
  
        function decorator(...args) {
          console.log('decorator()', ...args);
          return (target, key, descriptor) => {
            console.log('decorator(): target =>', target);
            console.log('decorator(): key =>', key);
            console.log('decorator(): descriptor =>', descriptor);
          };
        }
      `);
  
      class Hoge {
        @decorator
        instance = 1;
  
        @decorator
        method() {
          console.log('Hoge.prototype.method()');
        }
      }
  
      function decorator(...args) {
        console.log('decorator()', ...args);
        return (target, key, descriptor) => {
          console.log('decorator(): target =>', target);
          console.log('decorator(): key =>', key);
          console.log('decorator(): descriptor =>', descriptor);
        };
      }
  
      const hoge = new Hoge();
      hoge.method();
      hoge.instance;
    }
    console.groupEnd();
  }
  
new_contents: export default function decorators() {
    console.group('ES-next: Stage-2: decorators');
    {
      console.log(`
        class Hoge {
          @decorator
          instance = 1;
  
          @decorator()
          method() {
            console.log('Hoge.prototype.method()');
          }
        }
  
        function decorator(...args) {
          console.log('decorator()', ...args);
          return function(target, key, descriptor) {
            console.log('decorator(): target =>', target);
            console.log('decorator(): key =>', key);
            console.log('decorator(): descriptor =>', descriptor);
            return descriptor;
          };
        }
      `);
  
      class Hoge {
        @decorator
        instance = 1;
  
        @decorator()
        method() {
          console.log('Hoge.prototype.method()');
        }
      }
  
      function decorator(...args) {
        console.log('decorator()', ...args);
        return (target, key, descriptor) => {
          console.log('decorator(): target =>', target);
          console.log('decorator(): key =>', key);
          console.log('decorator(): descriptor =>', descriptor);
          return descriptor;
        };
      }
  
      const hoge = new Hoge();
      hoge.method();
    }
    console.groupEnd();
  }
  
subject: add a code of decorators