<h2>Introduction to the course</h2>Node.js Advanced is a course we&#x27;ve created to introduce the more complex side of development.<h2>Who is this course for?</h2>If you&#x27;re a developer with the basic and fundamental concepts of Node.js down, then this course is meant for you to discover the uncharted lands of Node.js.<h2>Recommendations for the course:</h2>Make sure you&#x27;ve completed our Node.js course to ensure the strong foundation you&#x27;ll be needing here.

Node.js Advanced

<h2>What does this lesson cover?</h2>The fixed area of the memory we call the Buffer class will be the topic of this lesson.Accessing the Buffer class is accessible without importing as it is a part of the Buffer Module, a core Node.js Module.The question we&#x27;ll answer is why exactly developers need to incorporate Buffers in code. Thus, we&#x27;ll create Buffers, write to Buffers, copy and decode Buffers, slice Buffers, and define Buffer Bytes.

Buffers

<h2>What does this lesson cover?</h2>We&#x27;ve referred to the fs module multiple times in the past lessons, however, the short description we&#x27;ve provided does not suffice and simply does not align with the importance of the fs module.This introduction scratches the service of the module that stores all the file query, manipulation functions and gives developers access to working with their computer’s file system.

Introduction

<h2>What does this lesson cover?</h2>The Understanding Streams lesson defines the usage and purpose of Streams and differentiates between the two types of Streams– Readable Streams and Writable Streams, Transform Streams, and Duplex Streams.We&#x27;ll also be expanding on the widely used mechanisms of Piping Streams and Chaining Streams by identifying where and how to use them in your Node.js application.

Understanding Streams

<h2>What does this lesson cover?</h2>This lesson covers a standard method of the fs module that has wide usage in Node.js applications by opening a file and thus allowing the reading and manipulating processes. We&#x27;ll also be identifying the elated concept of flags with corresponding examples that depict their usage.

Open a File

<h2>What does this lesson cover?</h2>File uploads take place when a user sends a request from a client machine to the server. This process is supported in Node.js with the help of the third-party Formidable Module.The said module permits various file uploads that we will be referring o in this lesson. With the help of the methods described in the lesson, developers will be able to upload forms, parse URLs, and save files.

Upload Files

<h2>What does this lesson cover?</h2>Information concerning the size of a file for example, or file permissions, and other characteristics that describe files are common info that developers might need to get their hands on at some point in time.This lesson covers the steps developers need to take to get that information with the help of methods you can find in the fs module.

Get File Information

<h2>What does this lesson cover?</h2>Sometimes, inputting a URL and a callback function is all you need to make a request. That said, the best approach may not always align with simple steps.The Request module covers advanced cases when making a request in Node.js.After learning how to install the Request Module we&#x27;ll use it in our Node.js application to create servers, follow redirects, etc.Each action is depicted in separate lessons with supporting examples and quizzes.

Request Module

Lesson Challenge

<h2>What does this lesson cover?</h2>There are a lot of ways for file reading, closing a file and file writing in Node.js. In this lesson, we&#x27;ll refer to the simplest and most efficient of the bunch in both cases.The methods described in the lesson will further develop your skills to work with files in Node.js.

Writing/Reading and Closing a File

<h2>What does this lesson cover?</h2>Node.js permits us to code an application for mail exchanges through third-party modules that require installation with the npm (Node Package Manager).This lesson will cover the exact syntax and structure of the said third-party module, thus, we&#x27;ll get into the process of incorporating that module into code and sending emails with our Node.js application.

Email

<h2>What does this lesson cover?</h2>Manipulating files in Node.js is standard practice, we&#x27;ve already assessed some methods regarding access properties, and now it&#x27;s time to learn how to truncate and delete Node.js files.The phrase truncate indicates changing the size of your Node.js files. In this lesson, we&#x27;ll assess the method used to truncate files, their syntax, and structure in code.Deleting files requires the use of a separate method that we&#x27;ll be referring to also.

Truncate and Delete a File

<h2>What does this lesson cover?</h2>Creating a directory in Node.js requires a sequence of steps which we&#x27;ll be analyzing in the following lesson.We&#x27;ll also be expanding on the reading, writing, and removing directories from your Node.js application. Each action requires a separate approach that we&#x27;ll digest in individual lessons with supporting code examples and quizzes.

Directories and methods

Truncate a File

The Node-powered fs.truncate() method is typically utilized for altering the size of the file. So either decreases it in size or increases it. The phrase “increasing/decreasing file size” indicates changes being made to the file at the path by len bytes.

Whenever len renders shorter than the length of the file, we call that truncating. Find its syntax below alongside the three parameters with their respective descriptions.

The first argument is path that takes on the file’s location. It can be displayed in either string type, url, or buffer.

Secondly, we have len that takes on the length value of the file after which it’ll go through a transformation and become truncated. len accepts integer values but, it also includes a default value of 0.

Lastly, we have callbacks that take on one error-related argument.

Select Correct Answer 

Elaborate on the following statement: “increase or decrease file size”

Which statement about len is true?

Example

To truly demonstrate how <samp>fs.truncate() </samp>works, vie wthe examples below.

When we run the above-written code (theoretically, it’s located in a .js file), only a single byte of content will remain in this file that’s been truncated.

You can find the logic behind the result in line <slot>4</slot>, the method reads <samp>fs.truncate(truncate, 1, err () { </samp> the first argument is the file path denoted under the truncate constant. Then we have the len value set at <slot>1</slot> and finally the error argument.

If we were to set the len value to <slot>0</slot>, meaning <samp>fs.truncate(truncate, 0, err ()</samp> the contents of the file would be whipped completely and it would no longer exist.

Fill Missing

Complete the<samp> fs.truncate() </samp>method.

 fs.writeFile() Method

An alternative approach to truncating files other than utilizing the <samp>fs.truncate()</samp> is <samp>fs.write()</samp>.

The method asynchronously writes definitive data to a file and manages truncating files in addition to that. To achieve that result, we’ll need to replace all file content with an empty string.

The parameters <samp>fs.writeFile() </samp>takes on are listed below with descriptions.

‣file that takes on String,url, integer, and Buffer inputs. The integer should indicate the location/path of the file.‣data takes on String, Buffer, DataView or TypedArray written to the file.‣options is an Object or String that provides definitive information on the parameter options.‣callback takes on one error-related argument.

Select Correct Answer

How does the <samp>fs.write() </samp>method truncate files?

What does the options parameter in the fs.write() method indicate?

Delete a File

The fs module permits data deletion with its <samp>fs.unlink() </samp>method.

The method is one of the more simpler methods of the fs module, it offers two parameters path and callback. Path indicates the name file is denoted, and the latter indicates a possibility of an error.

To better understand how it works, check the code-snippet below.

Firstly, we’ve initiates the fs module with the require() method, then we’ve added a related text in the consol log which as you’ve gathered, is completely customizable. Finally, we declared the <samp>fs.unlik()</samp> method with its two parameters (in the right order), meaning the path is <samp>input.txt</samp> and the call back is <samp>err</samp>.

To run the file (say, it’s called sample.js) run the following.

The output is gonna look something along the lines of:

Write Missing

Call the method that deletes file data.

<h2>What does this section cover?</h2>The incorporation of Buffers and Streams in React applications is a crucial step and this section covers the questions why? and how?After defining the buffers and everything developers can do with Buffers, we&#x27;ll introduce Streams, the types of Streams, and the fs module that is a requirement for using Streams.

Streams

<h2>What does this section cover?</h2>The Node.js File System stores all the file query, manipulation functions and gives developers access to working with their computer’s file system.This section covers the wide range of opportunities that the fs module offers developers to incorporate into their advanced Node.js code.We&#x27;ll be referencing different file manipulation methods, directories, access methods, but only after covering the basic operations and techniques.

File System

<h2>What does this section cover?</h2>Working with Node.js does not always entail limitations regarding core/built-in modules. In some cases, developers are meant to use third-party modules and packages to complete their application or incorporate features into their applications that are not available in the core/built-in Modules.This section will focus on uploading files, requests, and emailing with the help of packages.

Overview

Truncate a File

Example

fs.writeFile() Method

Delete a File