javascript - 重试 promise 直到解决(递归错误太多)

Question

我试图测试我是否可以重试 promise ，直到它解决，但它不断给出“太多递归”错误，我不明白为什么它在第三次递归后没有停止。

以下代码尝试模拟对服务器的失败查询请求，该请求来自非 promise 函数。

function nonPromiseCallback(x, resolve, reject){    
  if(x < 3){
    reject(x)
  }else{
    resolve(x)
  }
}

function tryUntilThree(x){
  return new Promise( (resolve, reject) => {
    nonPromiseCallback(x, resolve, tryUntilThree(x+1));
  })
}

tryUntilThree(1)
.then(console.log);

Answer 1

由于您对 promise 失败感兴趣，因此可以使用 catch 处理程序。

至于为什么你的代码不起作用，some 给出了很好的解释。 (也在评论中):

You get too much recursion because tryUntilThree is called too many times. Notice that you have written tryUntilThree(x+1), ie the engine has to resolve the call to tryUntilThree before it can call nonPromiseCallback. You have an infinite loop there.

function nonPromiseCallback(x, resolve, reject){    
  if(x < 3){
    reject(x)
  }else{
    resolve(x)
  }
}

function tryUntilThree(x){
  return new Promise( (resolve, reject) => 
    nonPromiseCallback(x, resolve, reject)
  ).catch(() => 
    tryUntilThree(x + 1)
  )
}

tryUntilThree(1)
.then(console.log);