承诺拒绝在回调内部不起作用

Question

我正在编写一个使用Google API的模块，但是在承诺中包装了所有基于回调的内容。这是问题区域的代码

file1.js

var File2 = require('file2')
var api = new File2()
api.auth().then(auth => {
  api.search('example').then(res => {
     ...do some stuff...
  })
}).catch(err => {
  console.log('1') //Not being run
  throw err
})

file2.js

class File2(){
  auth() {
    ...works fine and resolves...
  }

  search() {
     return new Promise((resolve, reject) => {
       googleapi.somemethod(options, (err, res) => {
         if(err) { 
           console.log('2') // DOES run
           reject(new Error(err))
         }
         resolve(res.field) //Program crashes here because reject didn't actually reject
       })
     })

}

对的调用auth工作正常，但是对search（更具体而言googleapi.somemethod）的调用失败了，并且err已定义。我检查错了，并console.log('2')运行，但随后console.log('1')在catch不运行时，没有引发错误，程序崩溃的resolve(res)原因res是不明确的。我尝试将错误捕获器作为第二个参数，then而不是使用catch，但这仍然不起作用

api.search('example').then(res => {
  ...do some stuff...
 }, err => {
    console.log('2') // Still doesn't run
    throw err
 })

我正在运行Node v6.2.1

Answer 1

您应该退还诺言：

var File2 = require('file2')
var api = new File2()
api.auth().then(auth => {
  return api.search('example').then(res => { // return the promise
     return ...
  })
}).catch(err => {
  console.log('1') // Not being run
  throw err
})

另外，如果您不需要auth内部，search则可以取消这些承诺：

var File2 = require('file2')
var api = new File2()
api.auth().then(auth => {
  return api.search('example')
}).then(res => {
   return ...
}).catch(err => {
  console.log('1') //Not being run
  throw err
})

Answer 2

调用reject()不会停止你的程序，下面的所有代码也将被执行。

请更新自

if(err) { 
  console.log('2') // DOES run
  reject(new Error(err))
}
resolve(res.field) //Program crashes here because reject didn't actually reject

到

if(err) { 
  console.log('2') // DOES run
  reject(new Error(err))
}
else {
  resolve(res.field) //Program crashes here because reject didn't actually reject
}

* 更新 * 或者您可以将代码缩短为

if(err) { 
  console.log('2') // DOES run
  return reject(err) // no need to new Error object
}
resolve(res.field) //Program crashes here because reject didn't actually reject