js promise async await的用法

aa(num){
      return new Promise((resolve,reject)=>{
        if(num>=10){
          setTimeout(()=>{
            resolve(200)
          },3000)
        }else{
          setTimeout(()=>{
            reject(400)
          },3000)
        }
      })
    },
    async bb(){
      console.log(1)
      await this.aa(9).then((res)=>{
        console.log(res)
      }).catch(err=>{
        console.log(err)
      })
      console.log(3)
    },

很清楚明白吧，哈哈