Deno Interview Questions and Answers for internship

0
Deno Internship Interview Questions and Answers

  1. What is Deno?

    • Answer: Deno is a modern runtime for JavaScript and TypeScript built on V8 (like Node.js), but with a focus on security, modern features, and a built-in dependency management system using URLs. It's designed to address some of the perceived shortcomings of Node.js.

  2. What are the key differences between Deno and Node.js?

    • Answer: Key differences include Deno's use of TypeScript support out-of-the-box, improved security model (permissions must be explicitly granted), built-in dependency management (using URLs), and a standardized module system (ES modules). Node.js traditionally uses CommonJS modules and requires separate package managers like npm.

  3. How does Deno handle dependencies?

    • Answer: Deno uses URLs to import dependencies directly from remote locations. This eliminates the need for a separate package manager like npm and simplifies dependency management. It also allows for easier version control and avoids dependency hell.

  4. Explain Deno's security model.

    • Answer: Deno operates in a sandboxed environment by default. It requires explicit permissions to access system resources like the network, file system, and environment variables. This enhances security by preventing unauthorized access.

  5. How do you import modules in Deno?

    • Answer: Modules are imported using standard ES module syntax (e.g., `import {someFunction} from "https://example.com/module.ts";`). The URL specifies the location of the module.

  6. What is the `deno run` command used for?

    • Answer: `deno run` executes a Deno script. It downloads dependencies specified in the script and runs the code. It also handles permissions requests.

  7. What is `deno test` used for?

    • Answer: `deno test` runs unit tests within a Deno project. Test files are typically named with the `.test.ts` extension.

  8. How do you handle asynchronous operations in Deno?

    • Answer: Deno uses Promises and async/await, which are standard JavaScript features, for handling asynchronous operations.

  9. Explain the use of top-level await in Deno.

    • Answer: Top-level await allows you to use `await` directly inside a module's top-level scope, simplifying asynchronous setup and initialization.

  10. What is the Deno standard library? Give examples.

    • Answer: The Deno standard library provides built-in modules for common tasks like file system access, HTTP requests, and more. Examples include `Deno.readFile`, `Deno.listen`, `Deno.writeTextFile`.

  11. How do you handle errors in Deno?

    • Answer: Errors are handled using try...catch blocks, similar to other JavaScript environments.

  12. Describe the process of creating a simple HTTP server in Deno.

    • Answer: Use `Deno.listen` to create a server, accept incoming connections, and handle requests using the `req` and `conn` objects. Send responses using `conn.write` or similar methods.

  13. How can you use Deno with a database like PostgreSQL?

    • Answer: You would need to use a third-party database driver compatible with Deno. Import the driver and use its API to interact with the database.

  14. What are some of the advantages of using TypeScript with Deno?

    • Answer: TypeScript brings static typing, improved code maintainability, better error detection at compile time, and better tooling support.

  15. How do you format code in Deno?

    • Answer: Deno supports code formatting using tools like `deno fmt`. This automatically formats the code to a consistent style.

  16. Explain the concept of modules in Deno and how they differ from Node.js modules.

    • Answer: Deno uses standard ES modules, while Node.js uses CommonJS modules. This leads to different import syntax and module resolution mechanisms.

  17. What are some of the common use cases for Deno?

    • Answer: Common use cases include building web servers, command-line tools, microservices, and backend applications.

  18. How does Deno handle environment variables?

    • Answer: Deno accesses environment variables through `Deno.env.get("VARIABLE_NAME")`. Requires appropriate permissions.

  19. What are some potential disadvantages of using Deno?

    • Answer: A smaller community compared to Node.js, fewer readily available third-party packages, and a potentially steeper learning curve for developers familiar with Node.js' ecosystem.

Thank you for reading our blog post on 'Deno Interview Questions and Answers for internship'.We hope you found it informative and useful.Stay tuned for more insightful content!