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首页 > 解决方案 > UnhandledPromiseRejectionWarning：未处理的承诺拒绝（拒绝 id：3）：

javascript - UnhandledPromiseRejectionWarning：未处理的承诺拒绝（拒绝 id：3）：

问题描述

我是新来的等待。我只是不知道如何处理所有等待错误和拒绝。总是有来自 shopify-api.js 函数的未处理拒绝，我无法打印来自我创建 index.js 的中间件的所有错误？

如何打印所有错误？我在等待正确处理吗？

index.js

const functions = require('firebase-functions');
const app = require('express')();
const cors = require('cors');

// Automatically allow cross-origin requests
app.use(cors({ origin: true }));

const asyncMiddleware = fn => (req, res, next) => {
    Promise.resolve(fn(req, res, next))
    	   .catch((err) => {
    	   		console.error(err);
    	   		res.json(err)
    	   	})
           .catch(next)
};


app.get('/v1/Test/Shopify', asyncMiddleware ( async (req, res, next) => {

	req.params.workshopId = "TEST_CR"
	req.params.date = "2018-11-30"
	req.params.startTime = "11:00"
	let result1 = await ShopifyWorkshop.AddDate(req, res, next)
	console.log("ShopifyWorkshop.AddDate: Success" .green)

	res.status(200).json({message: "Success"})
}));

exports.AddDate = async (req, res, next) => {
  await Helper.CheckParamsIsNull(req.params)

  let wsId = req.params.workshopId
  let wsDate = req.params.date
  let wsTime = req.params.startTime

  // Check if workshop is a level
  if (Helper.IsWorkshopType(wsId)) {
    return await Promise.all(WORKSHOP_TYPE[wsId].levelNames.map( async (typeName) => {
      WORKSHOP_CATEGORY[typeName].codeNames.map( async (codeName) => {
        for (let wsId in WORKSHOP_INFO) {
          if (WORKSHOP_INFO[wsId].codeName === codeName) {
            addVariant(wsId, wsDate, wsTime)
          }
        }
      })
    }))
  } else if (Helper.IsWorkshopCategory(wsId)) {
    return await Promise.all(WORKSHOP_CATEGORY[wsId].codeNames.map ( async (codeName) => {
    for (let wsId in WORKSHOP_INFO) {
      if (WORKSHOP_INFO[wsId].codeName === codeName) {
        await addVariant(wsId, wsDate, wsTime)
      }
    }
  }))
  } else {     
    return await addVariant(wsId, wsDate, wsTime)
  }
}

shopify-api.js 

exports.AddAProductVariant = async (id, options) => {
  	console.log("Adding variant to product..." + options.option1)

	let result = await shopify.productVariant.create(id, options)

	console.log("Added product variant: " + options.option1)
	return result
}

标签： javascriptfirebaseexpresspromiseasync-await

解决方案

在行中

async (typeName) => {
    WORKSHOP_CATEGORY[typeName].codeNames.map( async (codeName) => {
       …
    })
}

您正在创建一系列承诺，但随后忽略它们。在它们周围添加另一个Promise.all包装器，以便能够将所有它们的承诺返回到外部map：

(typeName) => {
    return Promise.all(WORKSHOP_CATEGORY[typeName].codeNames.map( async (codeName) => {
//  ^^^^^^^^^^^^^^^^^^
       …
    }))
}

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