<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

Defining Buffers

A Buffer class (implementation completed by the Node.js Buffer class) is a fixed area of memory, the concept is somewhat familiar to JS developers. The unalterable memory chunk is allocated outside the JavaScript V8 engine. For better imagining Buffers, think of them as integer arrays, representing data bytes, the Buffer class represents a storage (instances) for data.

The Buffer Module is one of the Core/Built-in modules of Node.js, thus developers are free to access the Buffer class without importing it beforehand.

<h2>Why do you need Buffers in Code?</h2>

Javascript was originally intended to manipulate HTML documents, but as of now, it’s known for managing strings and doesn’t have a byte type, just strings that take the form of numbers, structured types, and even byte arrays. Therefore, Node.js managed binary data by encoding every byte inside a text character, which was slow, wasteful, and difficult. To change the way binary handlings were carried out, Node includes a binary buffer implementation, which is JavaScript API under the Buffer pseudo-class. As mentioned in the parameters of the class buffer length is in bytes.

Select Correct Answer

True or False: A Buffer Class in an alterable area of not-fixed memory.

Creating a Buffer

Buffers can be created by utilizing many methods.

In this case, we’ve created a buffer from an encoded string. The encoding is set at default- UTF-8 as we have not specified otherwise.

Other accepted encodings include:

‣utf8 represents every character in the Unicode char. set. This encoding type is dominating the web and acts as the default method.‣ascii represents the ASCII character set as a method of encoding‣base64 encoding type implements binary data into an ASCII formatted string through a radix-64 translation (mostly used in textual documentation).

If the content for your buffer is not ready, you can use this method to create a buffer with a certain holding capacity (length) for future data inputs. Like so:

In the example above we’ve created a buffer with a length of<slot> 512 </slot>bytes.

Which method would be the right choice for creating a buffer if encoding needs specification?

Writing to Buffers

Though Buffers offers a wide range of functions to choose from (which we will be getting into soon), the overall syntax for writing to buffers is as follows:

‣ string (Data, that is to be written in the buffer using string.)‣ length (The number of permitted bytes for writing.)‣ offset (Default is set at 0, offset indicates the index of the in-use buffer.)‣ encoding (Default is set at UTF8 and notes the current encoding method.)

Write Missing

Complete the code by writing to buffer.

Buffer Bytes

After the process of receiving or creating a, the next step is inspection and the changing of contents (if required).

For gaining access to the byte value in the desired position (as a preface, the 5th position), we’ll be utilizing the [] operator as you can find below.

Please note than in the process of developing an intialized buffer, it will contain random bytes, excluding 0.

To manipulate the contents of the byte value in a given position:

The above code will set the 100th byte to 135.

To access the length of the buffer as whole,inquire the length property as such:

And afterwards, utilize the length to iterate over the contents of the buffer. Set and get byte value as demonstrated in the code-snippet below.

Now you develop a buffer with a capacity of your choosing (in this example 10) and set each byte with a value between 0 and 9.

Fill Missing

Copying and decoding a Buffer

Another key functionality of Buffers is copying. Developers can copy a part of a buffer into another through the<samp> copy() </samp>method, as demonstrated in the snippet below.

Positions<slot> 4</slot> to <slot>16 </slot>will be copied from our source buffer (buffer1) into the target buffer (buffer2).

A buffer can be converted into a UTF-8-encoded string as demonstrated below.

With the <samp>toString() </samp>method you have the ability to transcode a UTF-8 encoded string into a different encoding type, for instance, a base64.

Slicing a Buffer

Developers have the ability to extract a part of buffers (received or created). By extracting/slicing buffers, you can create another, small buffer. To do so, specify the starting and ending positions as demonstrated below.

An interesting aspect of slicing is that new memory is not allocated, this results of essentially no copying, the way slicing works is that the new buffer utilizes the parent buffer memory and uses different start and end points as reference.

There are however two things you need to be aware of when slicing buffers, firstly because the smaller buffer is simply an extraction of the old(parent) buffer, you need to keep the parent buffer around, getting rid of it will result in<samp><slot> memory leaks</slot></samp>.

And lastly, if any new changes are made to the parent buffer, even after slicing, they will apply to the child buffer as well. The fact that they are two different objects does not change that fact.

<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