Promise 似乎没有调用 resolve

Question

我有以下代码：const multer = require('multer');const multerUploadWorker = async(req, res, storage) => {    console.log('worker called');        const upload = multer({ storage: storage }).single('file');    upload(req, res, function (error) {        if (error) {            return Promise.reject();        } else {            console.log('resolve called');            return Promise.resolve();        }    });};module.exports = multerUploadWorker;和：const { success, fail } = require('../utils/response-util');const multer = require('multer');const multerUploadWorker = require('../workers/multer-upload-worker');const path = require('path');const upload = async(req, res) => {    const storage = multer.diskStorage({        destination: function (_, _, cb) {            cb(null, 'uploads/')        },        filename: function (_, file, cb) {            const ext = path.extname(file.originalname);            switch (ext) {                case '.jpg':                case '.JPG':                case '.jpeg':                case 'JPEG':                case '.png':                case '.PNG':                case '.gif':                case '.GIF':                    cb(null, Date.now() + ext);                    break;                default:                    cb('File type error', false);                    break;            }        }    });    try {        if (await multerUploadWorker(req, res, storage)) {            return success(res, { message: req.file });        }    } catch(error) {        return fail(            res, 'Something went wrong, please check the image type is \JPEG, GIF or PNG', '500'        );    }};module.exports = {    upload};似乎虽然控制台resolve called在multerUploadWorker其中记录并不会触发if (await multerUploadWorker(req, res, storage))条件。没有错误被抛出，只是没有任何反应。我在这里做错了什么？

Answer 1

您对 Promises 的使用不正确。multerUploadWorker应该返回承诺，但在你的情况下它什么也不返回。

const multer = require('multer');

const multerUploadWorker = async(req, res, storage) => {

    console.log('worker called');

    

    const upload = multer({ storage: storage }).single('file');

    return new Promise((resolve, reject) => {

        upload(req, res, function (error) {

        if (error) {

            reject(error)

        } else {

            console.log('resolve called');

            resolve();

        }

      });

    });

};

module.exports = multerUploadWorker;

同样是您处理结果的方式，无需检查结果，因为您没有返回布尔值，只需等待上传完成并在catch语句中处理错误的情况下：

    try {

       await multerUploadWorker(req, res, storage))

       return success(res, { message: req.file });

    }