Вопрос от вкатуна 36 лет от роду, который полторы недели назад решил вкатиться во frontend за зарплатой хотя бы 40 тысяч рублёв в провинции.

Читаю этот тред и темы Frontend вообще и охреневаю, как вы вообще не путаесь во всём этом нажористом свинарнике фреймворков. Какие-то next, nuxt, MobX, Redux и десятки других названий. Посмотришь на вакансию с требованиями к знанию всяких там фреймворков вроде Vue, там Vue2, Vuex, VueRouter с набором в 20 синтаксисов, Ангуляр кучи версий, LESS, SASS, SKSS, PostCSS, БЭМ, Figma, плюс некий axious, да какой-то WebRTC. Такое ощущение, что я читаю списки плагинов для Скайрима. Как вообще с таким кучей хрени переключаться между задачами, если требуют дизайн, React, Angular, Vue, Wordpress и управление базами данных одновременно?

Читаю и смотрю уроки про реакт, ощущение словно изучаю конструктор для обезьян которых посадили делать формы. И для этого требуются отдельные курсы которые выпускают React-разработчиков?
Отдельно напрягает рекомендованный способ удаления элементов из массива react-элементов со страницы, через filter с проверкой на совпадение нужного ключа с ключом каждого элемента в массиве. Зачем делать O(n) проверку всего массива, если можно использовать HashMap по ключу, или OrderedMap для сохранения порядка в массиве, тем более если возвращать каждый раз новый. Хотя подозреваю, что с максимум несколькими сотнями элементов на странице можно и забить на O(n), но в уроках об этом ни слова.

Когда-то баловался с JS и даже писал SPA на jQuery(необязательной) с внутренней структурой наподобие Virtual DOM, с event listeners использующими нужные data-атрибуты. Использовал Bootstrap, LESS, Jade/Pug, Grunt который заменил спустя время на webpack. Из-за не помню уже чего забил на эту тему, а сейчас шалею от того, сколько хлама навалили за это время.

Сижу сейчас, изучаю Typescript, читаю что джунов можно брать только до 25 лет, пока анус у них не огрубел, и понимаю, что проще будет изучать всё дальше, писать пет-проекты и заявляться на разговор о работе с ноги минуя HR.

На сколько вопросов сможете ответить из списка?

1. What is the relationship between Node.js and V8? Can Node work without V8?
2. How come when you declare a global variable in any Node.js file it’s not really global to all modules?
3. When exporting the API of a Node module, why can we sometimes useexportsand other times we have to usemodule.exports?
4. Can we require local files without using relative paths?
5. Can different versions of the same package be used in the same application?
6. What is the Event Loop? Is it part of V8?
7. What is the Call Stack? Is it part of V8?
8. What is the difference betweensetImmediateandprocess.nextTick?
9. How do you make an asynchronous function return a value?
10. Can callbacks be used with promises or is it one way or the other?
11. What Node module is implemented by most other Node modules?
12. What are the major differences betweenspawn,exec, andfork?
13. How does the cluster module work? How is it different than using a load balancer?
14. What are the--harmony-flags?
15. How can you read and inspect the memory usage of a Node.js process?
16. What will Node do when both the call stack and the event loop queue are empty?
17. What are V8 object and function templates?
18. What is libuv and how does Node.js use it?
19. How can you make Node’s REPL always use JavaScript strict mode?
20. What isprocess.argv? What type of data does it hold?
21. How can we do one final operation before a Node process exits? Can that operation be done asynchronously?
22. What are some of the built-in dot commands that you can use in Node’s REPL?
23. Besides V8 and libuv, what other external dependencies does Node have?
24. What’s the problem with the processuncaughtExceptionevent? How is it different than theexitevent?
25. What does the_mean inside of Node’s REPL?
26. Do Node buffers use V8 memory? Can they be resized?
27. What’s the difference betweenBuffer.allocandBuffer.allocUnsafe?
28. How is theslicemethod on buffers different from that on arrays?
29. What is thestring_decodermodule useful for? How is it different than casting buffers to strings?
30. What are the 5 major steps that the require function does?
31. How can you check for the existence of a local module?
32. What is themainproperty inpackage.jsonuseful for?
33. What are circular modular dependencies in Node and how can they be avoided?
34. What are the 3 file extensions that will be automatically tried by the require function?
35. When creating an http server and writing a response for a request, why is theend()function required?
36. When is it ok to use the file systemSyncmethods?
37. How can you print only one level of a deeply nested object?
38. What is thenode-gyppackage used for?
39. The objectsexports,require, andmoduleare all globally available in every module but they are different in every module. How?
40. If you execute a node script file that has the single line:console.log(arguments);, what exactly will node print?
41. How can a module be both requirable by other modules and executable directly using thenodecommand?
42. What’s an example of a built-in stream in Node that is both readable and writable?
43. What happens when the line cluster.fork() gets executed in a Node script?
44. What’s the difference between using event emitters and using simple callback functions to allow for asynchronous handling of code?
45. What is theconsole.timefunction useful for?
46. What’s the difference between the Paused and the Flowing modes of readable streams?
47. What does the--inspectargument do for the node command?
48. How can you read data from a connected socket?
49. Therequirefunction always caches the module it requires. What can you do if you need to execute the code in a required module many times?
50. When working with streams, when do you use the pipe function and when do you use events? Can those two methods be combined?

>>905548
1. Node.js is built on top of the V8 JavaScript engine, which is developed by Google and used in Google Chrome. V8 is responsible for executing JavaScript code and providing the runtime environment for Node.js. Node cannot work without V8.

2. In Node.js, each module has its own scope, and variables declared within a module are only accessible within that module by default. This is to prevent global namespace pollution and promote modularity.

3. When exporting the API of a Node module, we can use either exports or module.exports. The difference between the two is that exports is a reference to module.exports, so when we assign a value to exports, it modifies the reference and does not replace it. However, when we directly assign a value to module.exports, it completely replaces the reference. In most cases, using module.exports is preferred because it allows us to export a single object or function, while using exports allows us to add properties or methods to the exported object.

4. Yes, we can require local files without using relative paths by specifying the full path to the file. However, it is generally recommended to use relative paths for better portability and maintainability.

5. Yes, different versions of the same package can be used in the same application. Node.js uses a module resolution algorithm that allows different versions of a package to coexist in the same application. Each version of a package is installed in its own node_modules folder within its respective module's directory.

6. The Event Loop is a mechanism in Node.js that allows asynchronous non-blocking I/O operations to be performed efficiently. It is responsible for handling events and callbacks in an event-driven architecture. The Event Loop is not part of V8, but it works in conjunction with V8 to provide the event-driven programming model in Node.js.

7. The Call Stack is a data structure used by V8 to keep track of function calls and their execution context. It is a part of V8 and is responsible for managing the execution of JavaScript code.

8. setImmediate and process.nextTick are both mechanisms for scheduling asynchronous code to be executed in the next iteration of the event loop. The main difference between them is the order in which they are executed. process.nextTick callbacks are executed before any other I/O events or timers, while setImmediate callbacks are executed after I/O events but before timers.

9. An asynchronous function cannot directly return a value synchronously. Instead, it typically accepts a callback function as a parameter, and the result is passed to the callback when it becomes available. Alternatively, an asynchronous function can return a Promise object that represents the eventual result.

10. Callbacks and promises can be used together in Node.js. Promises provide a more structured and readable way to handle asynchronous operations, but callbacks can still be used if needed. In fact, many promise-based libraries in Node.js provide methods to convert callbacks into promises and vice versa.

11. The events module is implemented by most other Node modules. It provides an event-driven architecture for handling and emitting events.

12. spawn, exec, and fork are all methods for creating child processes in Node.js. The major differences between them are:
- spawn is used for launching a new process and provides a streaming interface for input/output.
- exec is used for executing a command in a shell and buffers the output.
- fork is used for creating a new Node.js process and allows for inter-process communication through message passing.

13. The cluster module in Node.js allows for the creation of multiple worker processes to handle incoming requests. It utilizes the underlying operating system's capabilities to distribute the workload among the workers. Usi

ng a load balancer, on the other hand, involves distributing requests among multiple servers or instances of Node.js.

14. The --harmony-flags are a set of command-line options that enable experimental ECMAScript features in Node.js. These features are not yet part of the official ECMAScript standard and may not be fully stable or supported.

15. Node.js provides the process.memoryUsage() method to read and inspect the memory usage of a Node.js process. It returns an object with properties such as rss, heapTotal, and heapUsed that provide information about the memory usage.

16. When both the call stack and the event loop queue are empty, Node.js will exit unless there are any active timers or pending I/O operations. In that case, it will wait for those operations to complete before exiting.

17. V8 object and function templates are used by the V8 engine to define the structure and behavior of JavaScript objects and functions. They provide a way to optimize memory usage and improve performance by predefining object layouts and function behaviors.

18. libuv is a multi-platform C library that provides asynchronous I/O operations, event handling, and other low-level system functionality for Node.js. Node.js uses libuv to handle I/O operations in a non-blocking manner and to manage the event loop.

19. To make Node's REPL (Read-Eval-Print Loop) always use JavaScript strict mode, you can set the NODE_REPL_MODE environment variable to 'strict'. This can be done by running NODE_REPL_MODE=strict node before starting the REPL.

20. process.argv is an array that holds command-line arguments passed to a Node.js process. The first element (process.argv[0]) is always the path to the Node.js executable, and the second element (process.argv[1]) is the path to the JavaScript file being executed. Additional command-line arguments are stored in subsequent elements of the array.

21. To perform one final operation before a Node process exits, you can listen for the 'exit' event on the process object. This event is emitted when the process is about to exit, and you can register a listener function to perform any necessary cleanup or final operations. The operation can be done asynchronously, but keep in mind that the process may exit before the asynchronous operation completes.

22. Some of the built-in dot commands that can be used in Node's REPL include:
- .help or .h: Show a list of available commands.
- .break or .b: Abort a multiline expression.
- .clear or .c: Clear the REPL context.
- .exit or .quit: Exit the REPL.
- .save or .load: Save or load the current REPL session to/from a file.
- .editor: Enter multiline mode and open a text editor to edit multiline expressions.