JEST：异步方法中的错误：ReferenceError：未定义 regeneratorRuntime [重复]答案

【问题标题】：JEST: Error in async method: ReferenceError: regeneratorRuntime is not defined [duplicate]JEST：异步方法中的错误：ReferenceError：未定义 regeneratorRuntime [重复]
【发布时间】：2020-09-20 03:47:09
【问题描述】：

我正在尝试在不获取数据的情况下测试与数据库的连接。为此，我制作了这个测试文件。

import { PGConnection } from "../../../db";

test('two plus two is four', () => {
    expect(2 + 2).toBe(4);
});

test("Test connection to DDBB", () => {
    const db = new PGConnection();

    let result = db.test();
    expect(result).toBe("Connection to database has been established succesfully");


});

我有一个类，我在其中创建与数据库的连接：

import Sequelize from "sequelize";
//It's mandatory to import dotenv in each file where we can use enviroment variables
import config from "dotenv";
config.config(); 

//console.log("Usuario DDBB: " + loader.FEB_CONNECTION_USER);


class PGConnection{
    constructor(){
        this.db = this.setConnection();
    }

    setConnection(){
        /*console.log("host: " + process.env.FEB_CONNECTION_HOST + "\n" + 
        "port: " + process.env.FEB_CONNECTION_PORT + "\n" + 
        "user: " + process.env.FEB_CONNECTION_USER + "\n" +
        "password: " + process.env.FEB_CONNECTION_PASSWORD + "\n" + 
        "database: " + process.env.FEB_CONNECTION_DDBBNAME);   */      
        return(
            new Sequelize(
                process.env.DDBB_NAME, 
                process.env.DDBB_USER,
                process.env.DDBB_PSWD, {
                    host: process.env.DDBB_HOST, 
                    port: process.env.DDBB_PORT,
                    define: {
                        freezeTableName: true, /**Don't add 's to the end of each table/model */
                        timestamps: false,  /**Don't add fields createdAt and updatedAt */
        /*                 charset: 'utf8',
                        dialectOptions: {
                            collate: 'utf8_general_ci'
                        },     */            
                    },
                    dialect: "postgres",
                    //Remove operatorAliases due to an error when we update to sequelize 6.0.0
                    //operatorsAliases: false,
                    pool: {
                        max: 5,
                        min: 0,
                        acquire: 30000,
                        idle: 10000
                    }
                }
            )
        );
    }

    async test(){
        try{
            console.log("host: " + process.env.FEB_CONNECTION_HOST + 
            "port: " + process.env.FEB_CONNECTION_PORT + 
            "user: " + process.env.FEB_CONNECTION_USER +
            "password: " + process.env.FEB_CONNECTION_PASSWORD + 
            "database: " + process.env.FEB_CONNECTION_DDBBNAME)
            await this.db.authenticate();
            console.log("Connection to database has been established succesfully");  
            return ("Connection to database has been established succesfully");
            //this.closeConnection();  
        }catch (err){
            console.error("Unable to connect to database: " + err);
            return("Unable to connect to database: " + err);
        }
     }    

    closeConnection(){
        this.db.close();
        console.log("Connection to database has been closed!!!")
    }
}

module.exports.PGConnection = PGConnection;

这个类工作正常。但是，当我尝试进行测试时，我遇到了这个错误：

 FAIL  src/server/tests/test.spec.js
  ● Test suite failed to run

    ReferenceError: regeneratorRuntime is not defined

      65 | 
      66 |     closeConnection(){
    > 67 |         this.db.close();
         |                                                   ^
      68 |         console.log("Connection to database has been closed!!!")
      69 |     }
      70 | }

我的 package.json 是：

{
  "name": "",
  "version": "1.0.0",
  "description": "Code to build an API for projects, users and tasks",
  "main": "",
  "scripts": {
    "dev": "babel-node src/server/server.js",
    "test": "jest ./server/tests"
  },
  "author": "",
  "license": "ISC",
  "dependencies": {
    "cors": "^2.8.5",
    "dotenv": "^8.2.0",
    "express": "^4.17.1",
    "helmet": "^3.22.0",
    "morgan": "^1.10.0",
    "pg": "^8.2.1",
    "pg-hstore": "^2.3.3",
    "sequelize": "^5.21.11"
  },
  "devDependencies": {
    "@babel/cli": "^7.10.1",
    "@babel/core": "^7.10.2",
    "@babel/node": "^7.10.1",
    "@babel/polyfill": "^7.10.1",
    "@babel/preset-env": "^7.10.2",
    "babel-loader": "^8.1.0",
    "jest": "^26.0.1",
    "webpack": "^4.43.0"
  }
}

我做错了什么？

【问题讨论】：

这个已经介绍过了，见stackoverflow.com/q/42535270/3001761
不完全！！！在那个问题中，解决方案是安装“babel-polifill”，我已经安装了它。我的问题是另一个不同的问题。尽管如此，感谢您的帮助！！！
骗子有六个答案，其中一个与下面相同。请滚动。
是的！！！你说的对！！！第五个答案是解决我的问题的方法！！！
嗨@jonrsharpe！！！是的，但只回答第 5 个问题。

标签： javascript node.js postgresql jestjs

【解决方案1】：

我找到了修复错误的解决方案。要修复它，您必须安装下一个插件：@babel/plugin-transform-runtime

npm install @babel/plugin-transform-runtime --save-dev

另外，你必须在 .babelrc 文件中配置插件：

"env": {
    "test": {
      "plugins": ["@babel/plugin-transform-runtime"]
    }
}

【讨论】：