TextEncoder and TextDecoder from the Encoding standard, which is polyfilled by the stringencoding library, converts between strings and ArrayBuffers:
var uint8array = new TextEncoder().encode("someString");
var string = new TextDecoder().decode(uint8array);
MDN Web Docs
developer.mozilla.org › en-US › docs › Web › JavaScript › Reference › Global_Objects › Uint8Array
Uint8Array - JavaScript | MDN
The Uint8Array typed array represents an array of 8-bit unsigned integers. The contents are initialized to 0 unless initialization data is explicitly provided. Once established, you can reference elements in the array using the object's methods, or using standard array index syntax (that is, ...
W3Schools
w3schools.com › jsref › jsref_typed_uint8array.asp
JavaScript Uint8Array
Uint8Array array represents a typed array of 8-bit unsigned integers.
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481
TextEncoder and TextDecoder from the Encoding standard, which is polyfilled by the stringencoding library, converts between strings and ArrayBuffers:
var uint8array = new TextEncoder().encode("someString");
var string = new TextDecoder().decode(uint8array);
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Here's what I use:
var str = String.fromCharCode.apply(null, uint8Arr);
GeeksforGeeks
geeksforgeeks.org › javascript › javascript-uint8array-from-method
JavaScript Uint8Array.from() Method - GeeksforGeeks
January 9, 2024 - The Uint8Array.from() method in JavaScript is used to create a new Uint8Array from an array-like or iterable object.
GitHub
github.com › stdlib-js › array-uint8
GitHub - stdlib-js/array-uint8: Uint8Array. · GitHub
var Uint8Array = require( '@stdlib/array-uint8' );
Author: stdlib-js
ThatSoftwareDude.com
thatsoftwaredude.com › content › 15283 › how-to-use-uint8array-base64-helpers-in-javascript
How to Use Uint8Array Base64 Helpers in JavaScript - ThatSoftwareDude.com
May 28, 2026 - Use native Uint8Array Base64 and hex helpers to encode and decode bytes without atob, btoa, Buffer, or hand-written conversion loops.
Bun
bun.com › guides › binary data › uint8array to arraybuffer
Convert a Uint8Array to an ArrayBuffer | Bun Guides
const arr = new Uint8Array(64); arr.buffer; // => ArrayBuffer(64)
npm
npmjs.com › package › uint8arrays
uint8arrays - npm
May 7, 2026 - This module exports a number of function that let you do common operations - joining Uint8Arrays together, seeing if they have the same contents etc.
» npm install uint8arrays
Published: May 07, 2026
Version: 6.1.1
Haxe
api.haxe.org › js › lib › Uint8Array.html
js.lib.Uint8Array - Haxe 4.3.7 API
The Uint8Array typed array represents an array of 8-bit unsigned integers. The contents are initialized to 0. Once established, you can reference elements in the array using the object's methods, or using standard array index syntax (that is, using bracket notation).
MDN
mdn2.netlify.app › en-us › docs › web › javascript › reference › global_objects › uint8array
Uint8Array - JavaScript | MDN
The Uint8Array typed array represents an array of 8-bit unsigned integers. The contents are initialized to 0. Once established, you can reference elements in the array using the object's methods, or using standard array index syntax (that is, ...
oliverrr's notes
oliverrr.net › notes › what-is-a-uint8array-and-why-does-it-exist-in-javascript
What is a Uint8Array and why does it exist in javascript? - oliverrr
Uint8Array is part of Javascript's Typed Array API which supports different configurations like 16-bit, 32-bit and 64-bit integers depending on the type of data you want to use.
Rust
docs.rs › js-sys › latest › js_sys › struct.Uint8Array.html
Uint8Array in js_sys - Rust
An Uint8Array() which creates an array with the given buffer but is a view starting at byte_offset for length elements.
GitHub
github.com › mdn › content › blob › main › files › en-us › web › javascript › reference › global_objects › uint8array › uint8array › index.md
content/files/en-us/web/javascript/reference/global_objects/uint8array/uint8array/index.md at main · mdn/content
> `Uint8Array()` can only be constructed with [`new`](/en-US/docs/Web/JavaScript/Reference/Operators/new).
Author: mdn
Evan Hahn
evanhahn.com › the-best-way-to-concatenate-uint8arrays
What's the best way to concatenate Uint8Arrays?
January 29, 2024 - For this problem, I wanted to write a function, concatenate, which took an array of Uint8Arrays as input and returned a single, combined Uint8Array as output.
Bun
bun.com › guides › binary data › arraybuffer to uint8array
Convert an ArrayBuffer to a Uint8Array | Bun Guides
const buffer = new ArrayBuffer(64); const arr1 = new Uint8Array(buffer); const arr2 = new Uint16Array(buffer); const arr3 = new Uint32Array(buffer); const arr4 = new Float32Array(buffer); const arr5 = new Float64Array(buffer); const arr6 = new BigInt64Array(buffer); const arr7 = new BigUint64Array(buffer);
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You can use the following in environments that support Array.from already (ES6)
var array = Array.from(uint8Array)
When that is not supported you can use
var array = [].slice.call(uint8Array)
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There is a method of Uint8Array using the prototype (but it only supported by Firefox and Chrome):
TypedArray.prototype.entries() --> it returns a array.
Check it out: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/TypedArray/entries
JavaScripture
javascripture.com › Uint8Array
Uint8Array JavaScript API
Interactive API reference for the JavaScript Uint8Array Object. Uint8Array is similar to an Array where each item is an 8 bit (1 byte) unsigned integer. Uint8Arrays cannot change size after creation.
Reddit
reddit.com › r/node › eli5: file, uint8array, buffer, arraybuffer, bytesarray, blob…
r/node on Reddit: ELI5: File, Uint8Array, Buffer, Arraybuffer, BytesArray, Blob…
December 16, 2021 -
I’m always ending up guessing.. I need to somehow understand. I have no idea what I’m doing when working with files. Just trying stuff until it works. Someone plz ELI5..
My current issue is getting a png file from Firebase storage which gives a “file” which I’m trying to add on a pdf, where the library expects a Uint8Array or Arraybuffer. I’ve been doing similar things before. But end up just guessing my way until it works, and this time.. well it doesn’t work. I guessed it all with no success. I don’t know what I’m doing so I guess I need to actually learn ;)
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A digital system, like a computer works on digital data, thus things which can be represented as digits. Or simpler: Computer sees a bit of numbers and works on them. Also a text is just a long number. Some time ago, one decided to have computers work on binary digits and to group 8 out of those as the typical size. That is a byte. (There were computers using other byte sizes, that's why sometimes, especially in network protocols, it is called octet) With a byte of eight bits you can represent 256 values. (From 0 to 255) over multiple decades there were discussions on representing text (actually that was prr-computer already with telegraphs etc) and one found the ASCII rules to map between numeric values and characters. Each letter in the English alphabet got a code. Thus the word Hello becomes the sequence of numbers 72 101 108 108 111 Now decimal system ia nice when counting with fingers, but not so good for a binary machine. As said we have the byte, thus instead ten digits is inconvenient so we use a number system with base 16, thus any digit can not only have ten different values (0 to 9) but 16 (0 to 9 and A to F) Thus the same numbers as above can be written in hex 0x48 0x65 0x6C 0x6C 0x6F Now each byte is represented by two hex digits which gives a nice structure (and if you notice that 0x41 is A and 0x61 is a you start to understand ASCII) Now over time 256 characters wasn't enough for represting text in all languages, so after many years and messing around with different code pages and encodings smart folks came up with Unicode and Utf-8 to encode all characters. Won't go there too deep, but in essence utf-8 uses the ASCII table for the first 128 characters (half a byte, the lower half) and all other characters use multiple bytes. The German letter Ä fornisntance is 0xC3 0x48. In addition the Unicode standard has specific rules on sorting and comparing those values and some fancy transformations. (Sorting rules are even language dependent, so the German Ä can be sorted like AE, behind Z or simply as A) Wenn Browsers and JavaScript were created it was decided that a string in JavaScirpt shall be Unicode data. This is logical as websites are full of human readable text and properties of Unicode are good (well, the story is more complicated there, but good enough) This was good for the time where Web was working with simple websites and JavaScript was doing minor text manipulation. However for lower layers of the compitong stack data is just a sequence of bytes. In memory you have bytes. A file is a sequence of bytes. The meaning of those bytes might be Unicode text, might be an image, might even be bianry program code all are just bytes. The difference is only in the one looking at it. Now treating all data as unicode string will do harm, as they have all the assumptions on top where only specific byte sequences are valid and so on. So something else had to be added. And in fact different groups added different things. Before we can explain that, one step more is needed: as said interpretation depends on who looks at the data. So back to our numbers and from decimal and hex to binary. As said 8 bit are a byte. The number 1 in binary with it 8 bits would look like 0b00000001 Here using 0b as prefix, so you interpret it as binary, not hey, not decimal. The value 127 inn inary looks like this: 0b01111111 all bits, but the first set. Now something fancy happens when we set the first bit to 1 as well: 0b11111111 This can either be 255 or -1. Wait what negative!? You will ask: Yes, there eisna problem with these numbers: Our byte has to represent negative numbers as well. And then the first digit tells us whether it's negative or positive. And whenever we look at the byte we have to make a choice how we look at it. Is it a text character? Is it a positive number? A negative number? The byte doesn't know and doesn't care only we when looking at it. Now the Uint8Array enters! By giving a sequence of bytes (some area in memory) to an Uint8Buffer we tell it "look at those bytes and treat tit like a sequence of bytes, where each byte is a 8 bit unsigned number" and by that we can work with those.bytes and each byte will be a number 0 to 256 and whatever we do with the array decides on what it does with those bytes. Maybe it is a pixel in an image, maybe an frequency on an audio file, maybe ... Now another term there eisnthe Buffer. A buffer is just some area in memory. An arrayBuffer is "this is my area of memory, but I haven't yet decided how i will interpret it" I said Buffer, I said complicazednhsorory ... That tis that Node.js developers Hand this issue before ArrayBuffer d Uint8Array was defined, so they created their own thing, which is similar to an Unit8Array (modern versions of Buffer are built on Uint8Array) but don't be confused, buffer is a generic term for some data stored somewhere, which is distinct from Buffer, which is a type in Node.js. Now there ris a bit more. 256 is a bit low formmany purposes. So you can group multiple bytes and make them digits in a larger number. Quite typical are efor 4 byte, which are 32 bit. Thus a Int32Array takes 4 bytes at once from the underlying data (the ArrayBuffer, the buffer, the memory region) and makes it a 32 bit signed number (- 2147483648 to 2147483647) the Uint32Array (0 to 4294967295) and if that isn't enought there are big(u)int64Array, which look at 8 byte at a time, which is also the number of byte/bit a modern CPU can store in it's register, transfer though bus and process the best, hence 64bit architecture. The key thing is: memory (RAM, disk or any other form) in modern computers is just a sequence of bytes and the way you look at it decides on the meaning. The computer doesn't know and you have to tell it. Uint8Array is the typically representation for low level work. ArrayBuffer is when you haven't decided, yet and all else are more special.
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it's a bit of a Pia esp when different libs want diff types. An ArrayBuffer is raw data. Like a big bag of data. You can't do anything with it - but if you convert it to something that can look inside the bag (Uint8Array), you can read / write it. If you just want to read, then Blob is your guy.
Bun
bun.com › binary data › convert a uint8array to a buffer
Convert a Uint8Array to a Buffer - Bun
July 25, 2026 - Use Buffer.from() to create a Buffer instance from a Uint8Array.