hexy.js -- utility to create hex dumps

Usage

hexy is an easy to use javascript library to create hex dumps. It works just
as well in Node.js, Deno, and browsers. It contains a number of options to
configure how the hex dump will end up looking.

It creates a pleasant looking hex dump by default:

``javascript
import { hexy } from 'hexy'

const b = Buffer.from("\000\001\003\005\037\012\011bcdefghijklmnopqrstuvwxyz0123456789")
// or String or Array containing numbers ( bytes, i.e. < 0xFF )

console.log(hexy(b))
`

CommonJS still works in modern Node.js via ESM interop:

`javascript
const hexy = require('hexy')
console.log(hexy.hexy(b))
`

results in this dump:

00000000: 0001 0305 1f0a 0962 6364 6566 6768 696a .......bcdefghij
00000010: 6b6c 6d6e 6f70 7172 7374 7576 7778 797a klmnopqrstuvwxyz
00000020: 3031 3233 3435 3637 3839 0123456789

Deno

hexy works natively in Deno using ES modules:

`typescript
import { hexy } from './hexy.js'

const data = new Uint8Array([0, 1, 3, 5, 31, 10, 9, 98, 99, 100])
console.log(hexy(data))
`

yields:

00000000: 0001 0305 1f0a 0962 6364 .......bcd

---

Browser Usage

For browsers, include as an ES module:

`html

`

Note: The HTML demo files (view.html, test.html) require serving from a
web server due to ES module CORS restrictions. They won't work when opened
directly as file:// URLs. Quick start:

`bash
python3 -m http.server 8000


Then open http://localhost:8000/view.html


`

Configuration

you can configure:
* Line width
* Format of byte grouping
* The case (upper/lower) of hex decimals
* Presence of the ASCII annotation in the right column.

This means it's easy to generate exciting dumps like:

0000000: 0001 0305 1f0a 0962 .... ...b
0000008: 6364 6566 6768 696a cdef ghij
0000010: 6b6c 6d6e 6f70 7172 klmn opqr
0000018: 7374 7576 7778 797a stuv wxyz
0000020: 3031 3233 3435 3637 0123 4567
0000028: 3839 89

or, if you want to get crazy, even:

0000000: 00 01 03 05 1f 0a 09 62 63 64 65 66 67 68 69 6a
0000010: 6b 6c 6d 6e 6f 70 71 72 73 74 75 76 77 78 79 7a
0000020: 30 31 32 33 34 35 36 37 38 39

Accepted Input

The input should be one of the following:

* a Buffer
* a String
* an Array containing Numbers. These should fit into 8 bits, i.e. be
smaller than 255. Larger values are truncated (specifically val & 0xff)



Formatting Options


Formatting options are configured by passing a config object to the hexy function:

`javascript
var config: {
bytesPerLine = 8, // how many bytes per line, default 16
bytesPerGroup = 2, // [0, 1, 2, 4, 8], number of bytes per group
// 0 = no delimiters, default 1 (changed in 0.4.0, previously 2)
showAddress = true, // show address column on the left, default true
radix = b, // [2, 8, 10, 16], the radix for numeral representation
// for the right column, default 16
littleEndian = true,// endianness of data, default false
// applies when bytesPerGroup > 1
extendedChs = true, // allow displaying more characters in the text column
// default false
caps = "lower", // ["lower"|"upper"], default lower
annotate = "ascii", // ["ascii"|"none"], ascii annotation at end of line?
// default "ascii"
prefix = p, // something pretty to put in front of each line
// default ""
indent = i, // number of spaces to indent every output line
// default 0
html = true, // funky html divs 'n stuff! experimental.
// default: false
offset = X, // generate hexdump based on X byte offset
// into the provided source
// default 0
length = Y, // process Y bytes of the provide source
// starting at offset. -1 for all
// default -1
displayOffset = Z, // add Z to the address prepended to each line
// (note, even if offset is provided, addressing
// is started at 0)
// default 0

// DEPRECATED (but still supported for backward compatibility):
width = n, // deprecated, use bytesPerLine instead
format = f, // deprecated, use bytesPerGroup instead
// ["none"|"twos"|"fours"|"eights"|"sixteens"]
numbering = n, // deprecated, use showAddress instead
// ["hex_bytes"|"none"]
display_offset = Z, // deprecated, use displayOffset instead
};

console.log(hexy.hexy(buffer, config));
`

In case you're really nerdy, you'll have noticed that the defaults correspond
to how xxd formats its output.



Installing



Either use npm (or whatever compatible npm thingie people are using these
days):

`shell
$ npm install hexy
`

It will also install hexy into your path in case you're totally fed up with
using xxd.

If you don't like npm, grab the source from github:

http://github.com/a2800276/hexy.js


Browser Support

Browser support is fixed (now supports Array and Uint8Array) in 0.3.3.
Please refer to test.html for examples. Note that because of the use of ES
module import syntax, hexy.js requires a modern browser (2018-2020+), the
script tag requires a type="module" attribute, and the test files must be
served from a web server.

`bash



TODOS

The current version only pretty prints node.js Buffers, and JS Strings and
(typed) Arrays. This should be expanded to also do Streams/series of Buffers
which would be nice so you don't have to collect the whole things you want to
pretty print in memory, and such.

I'd like to improve html rendering, e.g. to be able to mouse over the
ascii annotation and highlight the hex byte and vice versa, improve
browser integration and set up a proper build & packaging system.




Thanks

* Thanks to Isaac Schlueter [isaacs] for gratiously lending a hand and cheering me up.
* dodo (http://coderwall.com/dodo)
* the fine folks at Travis
* radare (https://github.com/radare)
* Michele Caini (https://github.com/skypjack)
* Koen Houtman (https://github.com/automagisch)
* Stef Levesque (https://github.com/stef-levesque)
* Abdulaziz Ghuloum (https://github.com/azizghuloum)
* rom-p (https://github.com/rom-p)

History

This started a fairly straightforward port of hexy.rb which does more or less the same thing. You can find it here:

http://github.com/a2800276/hexy

$3

* the init parameters no longer contain strings: all params are scalar-defined
* names of parameters have been changed to be more consistent

$3

* issue concerning static analysis and BigInt usage

$3

* introduced the concept of endiannes (googleable and wikiable). Before this
change, the code assumed that the displayed data is big-endian. However, most
file formats and most CPU architectures are little-endian. So, introduced
the support for it. The endiannes can be controlled by passing bool via
littleEndian, which defaults to false to support the behavior of the
previous versions
* introduced ability to group 8 bytes (16 nibbles). With prevalence of 64-bit
computing, the 64-bit (i.e. 8-byte) data is getting more and more popular.
The 8-byte grouping is enabled by passing "sixteens" into config.format
* introduced ability to display the binary data in bases (radixes) other than
hexadecimal: binary, octal, decimal and hexadecimal The radix is controlled
by passing 2, 8, 10 or 16 into config.radix
* introduced ability to control if non-printable characters are displayed or
replaced with '.'. To display extended characters, pass
config.extendedChs: true. The exact behavior of this flag depends on the
output type, html or not: In config.html: true mode, all the characters can
be displayed, even 0-0x20 have visual represenation. In config.html: false
mode, only the extended characters beyond the end of standard ASCII are
displayed.
* implemented and exported maxnumberlen() -- calculates how many characters
can a number occupy given bittness and radix
* several tweaks improved performance by ~15-30%, depending on the platform
(compared to v.0.3.2).
* a bit more order in the node.js tests:
* the tests are read from an uniform table. This allows enumerating the
testcases, as well as sharing them with browser tests
* added ability to do performance tests -- just run time node test perf
* enabled browser tests:
* visual summary with details of all the tests, collapsable and color-coded
* same set of testcases as in node.js
* all tests pass now. Found and fixed a bug that was present in all browsers
where they handle bigger-than-byte data differently compared to node.js
* created a static html page to hex display files (view.html)
* restricted the set of node.js versions and browsers (now requires support of
BigInt: Node.JS 10.4+, browsers since 2018-2020)
* the Travis-ci is passing now
* nits:
* removed some of unused variables
* increased formating consistency

### 0.3.2
* documentation typos
* 2FA for npm publish

### 0.3.1

* use strict
* fixes undefined var. Thanks m-kircher!

### 0.3.0

* adds typescript support. Thanks Abdulaziz!
* remove support for old node versions (0.6-0.12)

---

"Migration Guide" (0.3.x → 0.4.0)

$3


`javascript
// 0.4.0 - New API
hexy.hexy(buffer, {
bytesPerLine: 16,
bytesPerGroup: 2,
showAddress: true,
displayOffset: 0x1000
});
`

$3

`javascript
// Still works in 0.4.0 (backward compatible)
hexy.hexy(buffer, {
width: 16,
format: "fours", // maps to bytesPerGroup: 2
numbering: "hex_bytes", // maps to showAddress: true
display_offset: 0x1000 // maps to displayOffset: 0x1000
});
`

$3

- format: "none" → bytesPerGroup: 0
- format: "twos" → bytesPerGroup: 1
- format: "fours" → bytesPerGroup: 2
- format: "eights" → bytesPerGroup: 4
- format: "sixteens" → bytesPerGroup: 8`