then里不返回Promise

console.log('here we go')
new Promise(resolve=>{
    setTimeout(()=>{
       resolve('hello')
    },2000);
})
  .then(value=>{
       console.log(value)
       console.log('everyone');
       (function(){
           return new Promise(resolve=>{
              setTimeout(()=>{
                 console.log('Mr.Nan');
                 resolve('merry Xmas')
              },2000);
           });
       }());
       return false;
  })
  .then(value=>{
     console.log(value+'world')
  })

here we go

hello

everyone

false world       //当注释 return fasle ,不进行传值时   ，值为 undefined，    

Mr.Nan