Promise 的返回值 [英] return value from Promise

问题描述

考虑示例:

function returnValue () {
   return somePromise.then (
     function (someThing) {
       return {
         sucess: true,
         data: someThing
       }
     },
     function (someError) {
       return {
         sucess: false,
         data: someError
       }
     }
   )
}

Console.log (returnValue ())

我该怎么做才能真正拥有someThing"或someError"?而不是一个未决的承诺?

What should I do so that I actually have "someThing" or "someError"? And not a Promise pending?

请注意......当我在Meteor.methods"中编写这样的代码时，它的工作方式与我想要的完全一样，也就是说，它返回一个我返回给客户端的值，但在Meteor.methods"之外.方法"或在客户端(浏览器，使用或不使用任何框架)中，我拥有的是一个未决的承诺.

Just to note ... when I write a code like this within "Meteor.methods" it works exactly as I would like, that is, it returns a value that I return to the client, but outside of "Meteor.methods" or in the client (browser, using or not any framework) the one I have is a Promise pending.

推荐答案

传递给 .then() 的函数异步返回结果.已实现的 Promise 的 Promise value 将可用作传递函数的参数.Console.log (returnValue ())，正如您所指出的，记录的是 Promise 本身，而不是 Promise value.将 .then() 链接到 returnValue() 调用.另外，Console.log(returnValue())应该是console.log().

The function passed to .then() returns results asynchronously. The Promise value of the fulfilled Promise will be available as the argument of the passed function. Console.log (returnValue ()), as you noted, logs the Promise itself, not the Promise value. Chain .then() to returnValue() call. Also, Console.log (returnValue ()) should be console.log().

let somePromise = Promise.resolve("abc");

function returnValue () {
   return somePromise.then (
     function (someThing) {
       return {
         sucess: true,
         data: someThing
       }
     },
     function (someError) {
       return {
         sucess: false,
         data: someError
       }
     }
   )
}

returnValue().then(function(result) {
  console.log(result)
})

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