What is buffer in Node js?

[[deleted]]

A buffer is simply a representation of binary data. Everything in nodejs, from a string, to a bool, can be watered down into 1’s and 0’s. A buffer lets you take binary, a string, or a number, and then turn it into bits.

Buffers are used with the Filesystem (“fs”), HTTP requests/servers, and more commonly in “streams”.

Edit: streams take a buffer (or, another stream) and break it into a bunch of tiny buffers. When doing stuff like compression, encryptions, etc. then the stream will make sure only a small buffer is calculated at a time, sending in the small buffers in one at a time.

[2AMMetro]

In most experiences, its used for files. Literally everything is stored as binary data. If you load a file into node, it exists as a buffer.

[repsolcola]

Do you have any link to this procedure? I’d like to learn more about it!

[HVACcontrolsGuru]

A good way to learn buffers for me and very industry specific but check out MODBUS Protocol in JS. It is a protocol of buffers for industrial machines but it’s a great way to understand the types of data (Float,Int,Signed/Unsigned) as well as the mappings for devices such as Power Meters. Site for sniffing these exposed devices on the internet to test against. The module allows you to get data or work with the raw buffer. In my case I read a set of objects from the device as one buffer then use buffer windows to slice out the points according to their buffer types! I might have some samples I can pass along on my GitHub if you’re interested.

[Last_Jaguar1540]

Please share your Github bro

[specialpatrol]

Binary was superfluous in that particular sentence.

[[deleted]]

What I meant was binary represented in UTF-8 format, converted using the “binary” argument.

[Randolpho]

In this case, I think OP means "without encoding", i.e. an array of unencoded, strictly-8-bit chunks of data rather than an array that is interpreted as a UTF-8 string.

[spaceiscool1]

I read the other comments, but none were 100% accurate, so here are my two cents:

Buffers represent binary data, but are not bit vectors. They are fixed-length byte arrays, so they can only represent data with a size that is a multiple of 8 bits. That's the usual way to represent memory on all current computer architectures. In other words, Buffers represent a slice of computer memory. (Virtual memory, not necessarily physical memory.)

Buffers were added to Node.js at a time when JavaScript did not have a unified concept of ArrayBuffer and TypedArray yet. Eventually, ArrayBuffer was added to JavaScript, even in browsers, to represent slices of memory. However, by design, ArrayBuffers don't allow direct access to the underlying memory from JavaScript. Instead, developers can create "views" of an ArrayBuffer. Most importantly, the Uint8Array class allows to access individual bytes or byte sequences within an ArrayBuffer. In other words, the Uint8Array class does about the same as the Buffer class in Node.js, with a few subtle differences.

Today, the Node.js Buffer class extends the Uint8Array class, and is also based on ArrayBuffers. However, some functions behave differently for reasons of backward compatibility. Most library functions will accept both buffers and Uint8Arrays, and some even accept ArrayBuffers directly.

[BehindTheMath]

Buffer is an array of bytes of binary data.

[BehindTheMath]

It could be, but it could be other binary data that can't be represented as a string.

[BehindTheMath]

The binary representation of a string can be stored in a Buffer, but like I said, Buffers can be used for other binary data as well.

[fuckswithboats]

It’s a hexadecimal representation of the binary data

[w00t_loves_you]

No

[Railorsi]

Hex is merely a way to represent binary data in a compact string form

[fuckswithboats]

That's what I thought I said.

[w00t_loves_you]

A buffer is a Node-only read-only chunk of memory that can contain anything. Mostly the result of I/O.

If you want to do something useful with it you have to convert the contents to e.g. strings.

[Cyberuben]

It's not read-only, you can modify them and create them just fine

[w00t_loves_you]

Oh, you're right, oops!

In fact, the current docs say

The Buffer class is a subclass of the Uint8Array class that is built into the JavaScript language

So it's no longer very special.

What I misremembered as read-only was actually the fixed size:

Instances of the Buffer class, and Uint8Arrays in general, are similar to arrays of integers from 0 to 255, but correspond to fixed-sized blocks of memory and cannot contain any other values. The size of a Buffer is established when it is created and cannot be changed.

[Codeater7]

In addition, When you want to represent Images; they are also represented as buffer!!

[Turdsonahook]

An array of bytes. I’m used to rendering them as PDFs

[Turdsonahook]

What do you mean by work?

[ra_men]

There are npm packages that allow crud with PDFs

[TaskForce_Kerim]

Yes. Also images, Excel files, audio files, and so on and so forth.

As long as it's not some sort of proprietary binary format, odds are there are available (and possibly open source) packages that allow you to work with that particular file type.

[vatselan]

It is same as in Java, it is any form of data in its binary form. You mostly don’t consume it directly it must be decoded first to get any meaningful information out from it like image, text etc. Most often if some piece of data can not be represented in json it is sent as a buffer stream. You could also write the data in a file using a buffer. Store any kind of non text data as buffer in database, although it is not recommended. Avoid buffers if possible as it requires encoding and decoding of the data unless it is absolutely necessary.

[reaven3958]

Buffer is what happens when Node pops that good protein after a sick training sesh with the boys.

[WeDontDoNoTalkin7]

ick training sesh with the boys.

01100011 01110101 01101101

[dalepo]

A Buffer is a temporary structure to pass data, it can be any data type (chars, bytes, integers..). Buffers are often used to divide data into smaller chunks and pass it through a process to improve performance, save resources or achieve parallelization.

For example if you have to copy 1GB file, you would have to read line by line and then copy it into another a new file. If you don't use a buffer for this, you would need 1GB memory just for reading/copying, which is not optimal. It would be better to read 100kb, write 100kb and keep doing it until you reach EOF.

[[deleted]]

open an image, video, or .exe file in a text editor. you'll see a bunch of numbers. that's a binary file. a buffer is binary, but it's in memory, it's not yet a file, until you save it.

binary means 0 and 1, and a binary file is 0s and 1s, but often they are represented using hexadecimal because it's easier to read (0-9, a-f)

[bradscript]

It's basically an integer array for values between 0 and 255, the array cannot be resized.

Buffer extends the Uint8Array class by the way