Question

我有一个带有嵌套的promises数组的对象。

 let promise = new Promise(resolve => setTimeout(resolve, 1000, 'url'));
 let object = {
  registration: [promise, promise, promise],
   contract: [promise, promise, promise],
   businessLicense: [promise, promise, promise],
   businessPlan: [promise, promise, promise]
 };

我需要一个使用Promise.all

给出以下结果的函数

   resolvePromisesFunction(object).then(result => console.log(result))

   // the output should be
   {
     registration: [ 'url', 'url', 'url' ],
     contract: [ 'url', 'url', 'url' ],
     businessLicense: [ 'url', 'url', 'url' ],
     businessPlan: [ 'url', 'url', 'url' ]
   }

THX！

Answer 1

您可以将chaining promises与Promise.all一起使用：

＆＃13;

let promise = new Promise(resolve => setTimeout(resolve, 1000, 'url'));
var obj = {
   registration: [promise, promise, promise],
   contract: [promise, promise, promise],
   businessLicense: [promise, promise, promise],
   businessPlan: [promise, promise, promise]
 };
 
function resolvePromisesFunction(obj) {
 let resolvedObj = {};
 return Promise.all(Object.keys(obj).map(service => {
   return Promise.all(obj[service])
      .then(result => resolvedObj[service] = result);
 })).then(result => resolvedObj);
  
}

resolvePromisesFunction(obj).then(result => console.log(result));

＆＃13;

Answer 2

尝试迭代已知的承诺，Promise.all，然后Promise.all结果。

＆＃13;

let promise = new Promise(resolve => setTimeout(resolve, 1000, 'url'));
let object = {
  registration: [promise, promise, promise],
  contract: [promise, promise, promise],
  businessLicense: [promise, promise, promise],
  businessPlan: [promise, promise, promise]
};

const promises = [];
Object.keys(object).forEach(key => {
  promises.push(Promise.all(object[key]));
});

Promise.all(promises).then(result => {
  const returnedObject = {};
  result.forEach((value, index) => {
    returnedObject[Object.keys(object)[index]] = value;
  });
  console.log(returnedObject);
});

＆＃13;

Answer 3

这是一个解析深层嵌套对象递归的方法。寻找所有承诺没有其他对象或阵列的深度

// Resolves array
const promiseMap = (promiseList, functor) => 
  Promise.all(promiseList.map(promiseOrValue =>
    Promise.resolve(promiseOrValue).then(functor)
  ))

// Resolves objects
const promiseProps = obj =>
  Promise.all(Object.keys(obj).map(key =>
    Promise.resolve(obj[key]).then(val => {
      obj[key] = val;
    })
  )).then(() => obj)

// Resolves recrusive deep objects
const resolveNestedPromises = obj =>
  Promise.resolve(obj).then(obj => {
    if (Array.isArray(obj)) {
      return promiseMap(obj, obj => resolveNestedPromises(obj));
    }
    else if (obj && typeof obj === 'object'  && obj.constructor === Object) {
      const obj2 = {};
      for(const key in obj) {
        obj2[key] = resolveNestedPromises(obj[key]);
      }
      return promiseProps(obj2);
    }
    return obj;
  })

let promise = new Promise(resolve => setTimeout(resolve, 1000, 'url'));
let object = {
registration: [promise, promise, promise],
 contract: [promise, promise, promise],
 businessLicense: [promise, promise, promise],
 businessPlan: [promise, promise, promise]
};

promiseProps(object).then(console.log) // or 
resolveNestedPromises(object).then(console.log)

具有嵌套的Promises数组的对象

3 个答案: