Question

我很难尝试停止promise中的循环。这是我的方法。这有什么问题吗？

 Promise.all(myArray.map((obj) => {
      this.someFunction(obj);
 }))

这是我调用的函数。

someFunction(){
 return new Promise(function (resolve, reject) {
    ....
     reject()
 })}

Answer 1

我已经更新了代码，它已经过测试，并且可以与我提供的模拟数据一起在我的机器上运行。我不确定您的其余代码的结构如何，但这是这样的：哦，您不能突围地图，但是我们将使用一个简单的for循环，因为我们可以突围一下：

function someFunction(){
 return new Promise(function (resolve, reject) {
      // I will be rejeccting a boolean
      // If you are resolving something, resolve it as true
     reject(false)
 })}


async function shouldStopLoop(){

  // the boolean will come here
  // if it is false, the catch block will return
  // if it is true, the try block will return

  let stopLoop = null;
  let result = null;

  try {
     result = await someFunction();
     return result
  } catch(error) {
    stopLoop = error;
    return stopLoop;
  }
}

function mayReturnPromiseAll() {

  let myArray = ['stuf to loop over...']
  let arraytoGoInPrimiseAll = [];


  // Array.prototype.map cannot be stopped
  // Thats why we will use a for loop and we will push the data we need
  // into another array 
  for (var i = 0; i < myArray.length; i++) {
    if (!this.someFunction(obj)) {
        break;
    } else {
      // push things in arraytoGoInPrimiseAll
    }
  }

  if(arraytoGoInPrimiseAll.length > 0){
    return Promise.all(arraytoGoInPrimiseAll)
  } else {
    // do something else
  }

};

Answer 2

尝试一下：

const arrayOfFunctions = myArray.map(obj => this.someFunction(obj))
Promise.all(arrayOfFunctions).then(values => {
 console.log(values);
}).catch(error => {
  console.log(error)
});

拒绝时如何停止Promise.all循环

2 个答案: