35 Questions
What is the purpose of using modules in Node.js?
To enhance code organization and reusability
How can you access built-in modules in Node.js?
Using the require() function
What is the purpose of the module wrapper function in Node.js?
Encapsulating the module code within a function
How does Node.js achieve module caching?
By storing a copy of the module's exports object after the first require() call
In Node.js, how can you create and use local modules?
By defining reusable code blocks specific to your project and storing them within the project directory
What does module.exports do in Node.js?
Exports an object that represents the module's public interface
What is the purpose of the module wrapper function in Node.js?
To load and execute the module code and cache the module's exports object
Why does Node.js use module caching?
To improve performance by caching the result of loading and compiling modules
What happens when a module is cached in Node.js?
It is stored and its exports object is cached for subsequent use
Which tool is used for managing project dependencies in Node.js?
NPM (Node Package Manager)
What is the purpose of creating a package.json file in Node.js?
To provide general information about the project and manage dependencies
Where are modules stored in a Node.js application?
Inside the app's node_modules folder
What does Node.js do before executing a module's code?
Wraps it with a function wrapper
Why does Node.js utilize module caching?
To improve performance by caching loaded and compiled modules
How does Node.js handle the caching of modules?
Load, execute the module code, and cache the module's exports object
In Node.js, what is the purpose of the module wrapper function?
Wraps any code inside a JavaScript file before execution
How can you share functions and variables between modules in Node.js?
Using module.exports to export functions and variables
What is one way to create and use local modules in Node.js?
Using relative paths to require them in your application
Which file is created when initializing npm and going through all settings?
package.json
What is the purpose of devDependencies in a Node.js project?
Only necessary for development
When setting up a Node.js project, what will applications include?
dependencies and devDependencies
What does the '-y' flag do when adding dependencies using npm?
Select all defaults automatically
Why is separating dependencies and devDependencies in a Node.js project considered a helpful practice?
To determine which dependencies are only for development
What is the purpose of a module wrapper function in Node.js?
To bundle all code within a function scope
How does Node.js achieve module caching?
By storing modules in a centralized module cache for reuse
What is the purpose of the require() function in Node.js?
To import built-in modules or dependencies
When setting up a Node.js project, what is the role of a package.json file?
Define the project's dependencies and metadata
What role does NPM play in managing dependencies in Node.js projects?
Handles installation, updating, and removal of project dependencies
In Node.js, what is the main benefit of module caching?
Improves application performance by reducing duplicate loading
What is the purpose of the module wrapper function in Node.js?
To wrap the entire code inside a function before execution
How does module caching work in Node.js?
It saves modules globally to prevent them from being loaded multiple times
What does the module.exports syntax achieve in Node.js?
It allows selective exporting of variables and functions
In Node.js, how can you create and use local modules?
By using module.exports and require syntax
What happens if you don't use module.exports in a Node.js module?
The functions and variables within the module are private to that module only
Why is it essential to promote separation of concerns within an application?
To improve reusability and maintainability of the codebase
Study Notes
Node.js Modules
- Modules are reusable blocks of code that provide functionalities you can integrate into your applications, promoting code organization, reusability, and separation of concerns.
Built-in Modules
- Built-in modules come bundled with Node.js installation, providing essential functionalities for common tasks like file system access, networking, I/O operations, etc.
- Can be accessed using the require() function in your code.
- Examples: const OS = require('os'); console.log(OS.arch())
Local (User-defined) Modules
- Local modules are reusable code blocks created specifically for your project and stored within the project directory.
- Offer a way to organize your codebase, improve reusability, and promote separation of concerns within your application.
- Local module is just a file with a .js extension (e.g., test.js).
Module Wrapper
- NodeJS wraps the entire code inside a function before execution, known as the Module Wrapper Function.
- The Module Wrapper Function has the following structure: __dirname, __filename are variables that hold the name and directory of the current module.
Module Caching
- Module caching is a feature that helps improve performance by caching the result of loading and compiling modules.
- When a module is required by another module, Node.js will load and execute the module code, and then cache the module's exports object.
NPM (Node Package Manager)
- NPM is a tool for managing project dependencies via the command line and a website hosting over 1 million third-party packages.
- Modules are shared as packages, which extend the functionality of your app, and are stored in the app's node_modules folder.
Initializing NPM and Creating a package.json file
- Initializing npm will create a package.json file within the root of your application folder, containing general information about the project.
- Can be initialized using the command-line: npm init, or with defaults: npm init -y.
Adding Dependencies
- Applications can include both dependencies and devDependencies, or just dependencies.
- devDependencies are thought of as dependencies that are only necessary for development.
- Adding dependencies can be done using the npm install command.
Test your knowledge on organizing codebase, improving reusability, and promoting separation of concerns in JavaScript applications. Learn about local modules in JavaScript and how module.exports can be used to define functions and variables across modules.
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