J World

  While working on a project with MongoDB after a long hiatus, I stumbled upon an unexpected error that stopped me in my tracks: 🚨 Error Message: The signature ‘(inputId: number): ObjectId’ of ‘ObjectId’ is deprecated. At first glance, this seemed unusual. I couldn’t recall seeing this error before, and it left me scratching my head. But as we all know, the world of IT evolves at an astonishing pace. Taking even a short break from the field can leave you feeling like a lot has changed overnight. If you’ve ever been in a similar situation, you’ll know the mix of frustration and determination that kicks in when you encounter an unfamiliar error. Thankfully, after some digging and testing, I found the solution. Here’s a breakdown of the issue, what caused it, and how I resolved it. Understanding the Problem What is ObjectId? ObjectId is a MongoDB data type commonly used for unique identifiers. It’s crucial for database records, especially in situations where you need to generate...

  When working on a project with a React.js frontend and a Nest.js backend, encountering CORS (Cross-Origin Resource Sharing) errors is almost a rite of passage. If you’ve ever seen the dreaded message: XMLHttpRequest at 'http://localhost:3000/user/' from origin 'http://localhost:3001' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. …then you know how frustrating this issue can be. However, it’s such a common problem that it doesn’t faze me anymore. 😅 In this article, I’ll explain what causes this error, why it occurs, and how to resolve it effectively in a Nest.js backend environment. What is CORS? CORS, or Cross-Origin Resource Sharing, is a security feature implemented by web browsers. It prevents a frontend application running on one origin (e.g., http://localhost:3001 ) from accessing resources hosted on a different origin (e.g., http://localhost:3000 ) without explicit permission. Why C...

  While working on test cases for a NestJS application, I encountered a peculiar TypeScript error that halted my progress: 🚨 Error Message: _Type ‘Promise<{ userName: string; }>’ is not assignable to type ‘Promise<(Document<unknown, {}, UserDoc> & UserDoc & Required<{ id: unknown; }>)[]>.’ This error was not only unexpected but also a bit frustrating at first. It highlighted a type mismatch issue in one of my Jest tests, specifically when using jest.spyOn . If you’ve worked with TypeScript and testing frameworks like Jest, you know how common type issues can be when dealing with mocked functions. In this article, I’ll walk you through what caused this error, the steps I took to troubleshoot it, and how I ultimately resolved it by properly typing jest.spyOn . Understanding the Error What Does the Error Mean? The error essentially points to a type mismatch between the value being returned by a mocked function and the type expected by TypeScr...

  I had only used Nest.js a couple of times a few years ago, but I decided to dive back into it recently. I started by following a tutorial on YouTube and successfully connected to Mongoose without any issues. However, the problem arose when I ran the tests. While yarn start:dev worked perfectly without any errors, running yarn test began to throw errors: Nest can't resolve dependencies of the UserService (?). Please make sure that the argument "UsersModel" at index [0] is available in the RootTestModule context. Unsure of what this error meant, I turned to the internet for solutions. Case 1: Someone suggested that it might be due to duplicate imports and advised checking if service.ts was imported more than once in app.module.ts or elsewhere. After thoroughly inspecting my code, I found no duplicate imports. Case 2: Another suggestion was to add this part to module.ts : @Module ({ controllers : [UserController], providers : [ UserService, { provide : ge...

  While setting up a new NestJS project, I encountered an unexpected roadblock — an error message that read: 🚨 “Failed to execute command: npm install — silent.” 🚨 At first, I was perplexed, but instead of panicking, I took a step back and started researching potential causes. After scouring online forums and developer communities, I discovered that this issue is commonly linked to network infrastructure challenges specific to Korea. Troubleshooting Steps I Took: Checked My Internet Connection Sometimes, unstable or slow network speeds can interfere with package installations. However, my connection seemed fine. Cleared npm Cache Running npm cache clean --force didn't seem to resolve the issue. Tried an Alternative Installation Approach Switching to a different package manager, Yarn , was suggested in several online discussions. The Solution That Worked: Instead of sticking with npm , I decided to give Yarn a try by running the following command: yarn install To my r...