JavaScript Arraybuffer to Hex

Javascript ArrayBuffer to Hex

function buf2hex(buffer) { // buffer is an ArrayBuffer
  return [...new Uint8Array(buffer)]
      .map(x => x.toString(16).padStart(2, '0'))
      .join('');
}

// EXAMPLE:
const buffer = new Uint8Array([ 4, 8, 12, 16 ]).buffer;
console.log(buf2hex(buffer)); // = 04080c10

How to convert a hexadecimal string of data to an ArrayBuffer in JavaScript

You could use regular expressions together with Array#map and parseInt(string, radix):

var hex = 'AA5504B10000B5'
var typedArray = new Uint8Array(hex.match(/[\da-f]{2}/gi).map(function (h) {  return parseInt(h, 16)}))
console.log(typedArray)console.log([0xAA, 0x55, 0x04, 0xB1, 0x00, 0x00, 0xB5])
var buffer = typedArray.buffer

Byte array to Hex string conversion in javascript

You are missing the padding in the hex conversion. You'll want to use

function toHexString(byteArray) {
  return Array.from(byteArray, function(byte) {
    return ('0' + (byte & 0xFF).toString(16)).slice(-2);
  }).join('')
}

so that each byte transforms to exactly two hex digits. Your expected output would be 04812d7e3a9829e5d51bdd64ceb35df060699bc1309731bd6e6f1a5443a7f9ce0af4382fcfd6f5f8a08bb2619709c2d49fb771601770f2c267985af2754e1f8cf9

How to convert Buffer array to hex?

You can just create a new buffer and convert it into the format you need.

var o = {"hash": {
"type": "Buffer",
"data": [
  151,
  14,
  51,
  26,
  46,
  52,
  5,
  151,
  99,
  107,
  38,
  188,
  138,
  180,
  76,
  56,
  108,
  214,
  135,
  213,
  125,
  134,
  105,
  139,
  129,
  236,
  206,
  157,
  67,
  1,
  12,
  12
  ]
 }
}

console.log(new Buffer(o.hash,'hex').toString('hex'));
// 970e331a2e340597636b26bc8ab44c386cd687d57d86698b81ecce9d43010c0c

Convert hex string to ArrayBuffer

One simpler option is to use teh package hex-to-array-buffer on npm where you can simply use teh function hexToArrayBuffer and convert the hex string to an array buffer.

You can also do it by yourself by doing:

var hex = your hex
var typedArray = new Uint8Array(hex.match(/[\da-f]{2}/gi).map(function (h) {
  return parseInt(h, 16)
}))
var buffer = typedArray.buffer

Convert Binary ArrayBuffer/TypedArray Data to Hex String

There are two ways who you can read the bytes, Big-Endian and Little-Endian.

Well, the "checksum" who you provide is a "hex" in Little-Endian. So we can create a buffer and set the number specifying the Little-Endian representation.

// Create the Buffer (Uint32 = 4 bytes)
const buffer = new ArrayBuffer(4);

// Create the view to set and read the bytes
const view = new DataView(buffer);

// Set the Uint32 value using the Big-Endian (depends of the type you get), the default is Big-Endian
view.setUint32(0, 1648231196, false);

// Read the uint32 as Little-Endian Convert to hex string
const ans = view.getUint32(0, true).toString(16);

// ans: 1c033e62

Always specify the 3rd parameter in DataView.setUint32 and the 2nd in DataView.getUint32. This defines the format of the "Endian". If you don't set it you can get unexpected results.

Convert Uint8Array into hex string equivalent in node.js

You can use Buffer.from() and subsequently use toString('hex'):

let hex = Buffer.from(uint8).toString('hex');

How to convert a hexadecimal string to Uint8Array and back in JavaScript?

Vanilla JS:

const fromHexString = (hexString) =>
  Uint8Array.from(hexString.match(/.{1,2}/g).map((byte) => parseInt(byte, 16)));

const toHexString = (bytes) =>
  bytes.reduce((str, byte) => str + byte.toString(16).padStart(2, '0'), '');

console.log(toHexString(Uint8Array.from([0, 1, 2, 42, 100, 101, 102, 255])));
console.log(fromHexString('0001022a646566ff'));

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