为什么我得到承诺而不是价值? [英] Why am I getting Promise instead of a value?

问题描述

我想我不明白，为什么我得到 Promise 作为回报?我需要创建对象.从promise返回值的两个选项都不起作用.

I think I do not understand, why am I getting Promise in return? I need to create object. Both options to return a value from promise do not work.

为什么会这样?我想念什么?

Why is it so? What am I missing?

解决方案:在 t().then(res => {const myVar = {...}})

// a.js
exports.t = (key, lang, props) => {
    return i18next.changeLanguage(lang).then(t => {
        return t(key, props);
    });
};

// b.js
import {t} from './a.js'
const myVar = {
  a: "a",
  b: "b",
  c: (()=>{
     switch (template) {
       case 'a':
         // Promise should return value here from t();
       default:
         break; 
     }
  })(),
  d: (async () => {
     switch (template) {
       case 'a':
         // Not working, returns Promise... Why?
         return await t('email.Registration Confirmation', lng);
       default:
         break; 
     }
  })(),
  e: (()=>{
     switch (template) {
       case 'a':
         // Not working, returns Promise... Why?
         return t('email.Registration Confirmation', lng).then(res => {
           return res;
         });
       default:
         break; 
     }
  })()
}

JavaScript是否有可能等待该 Promise 解析，然后完成创建对象?

Is it possible at all, that JavaScript waits for that Promise to be resolved, and then finishes creating an object?

推荐答案

async 和 await 是通过允许您使用来管理承诺的工具在 async 函数内部似乎不异步的语法.

async and await are tools to manage promises by letting you use syntax that appears to be non-asynchronous inside an async function.

因此， async 函数将总是返回一个诺言(当其中的所有诺言都得到解决时，它将解析为返回值之和).

Consequently, an async function will always return a promise (which will resolve to whatever the return value is when all the promises inside it have resolved).

您在 case'Register':之后的功能上有误.它返回一个承诺.您没有代码来检查返回的内容.

You are wrong about the function after case 'Register':. It returns a promise. You have no code to examine what it returns though.

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