1. 

// 输出1和3， 2不会输出
      const p = new Promise(() => {
        console.log(1)
      })

      p.then((res) => {
        console.log(2)
      })

      console.log(3)

promise实例_mklink

2.

// 先输出3，在输出then:success1，不会输出catch
      const p = new Promise((resolve, reject) => {
        resolve('success1')
        reject('error1')
        resolve('success2')
      })

      p.then((res) => {
        console.log('then:', res)
      }).catch((err) => {
        console.log('catch:', err)
      })

      console.log(3)

promise实例_mklink_02