!Debundle

This is a tool built to unpack javascript bundles prudiced by webpack and browserify.

scil/reliable-debunble

Installation

``
npm i -g @scil/reliable-debundle
`

how to use in shell, step by step

`bash
$ debundle
Usage: debundle [input file] {OPTIONS}

Options:
--input, -i Bundle to debundle
--output, -o Directory to debundle code into.
--config, -c Configuration file

$ curl https://raw.githubusercontent.com/1egoman/debundle/master/test_bundles/browserify/bundle.js > bundle.js
$ curl https://raw.githubusercontent.com/1egoman/debundle/master/test_bundles/browserify/debundle.config.json > debundle.config.json
$ cat debundle.config.json
{
"type": "browserify",
"knownPaths": {}
}
$ debundle -i bundle.js -o dist/ -c debundle.config.json
$ tree dist/
dist/
├── index.js
└── node_modules
├── number
│   └── index.js
└── uuid
├── index.js
├── lib
│   ├── bytesToUuid.js
│   └── rng.js
├── v1.js
└── v4.js
4 directories, 7 files
`

Preferable configuration for webpack

The simplest way is use "replaceRequires": "variable",
but in the produced js files, n(1) would not support code jumping in Intellij Idea family products currently.
To use code jumping, wait for a better Intellij Idea, or use "replaceRequires": "inline,variable",

`json
{
"type": "webpack",
"entryPoint": 0,
"moduleAst": ["body", 0, "expression", "argument", "arguments", 0],

"keepDeeperThan": 3,
"inDescendantsOfSameNameDeclaraton": "keep",

"replaceRequires": "inline,variable",
"replaceModules": "variable",
"replaceExports": "variable",
"variableType": "const",

"require_visitors": {
"convertRequireBind": {
"enable": 1
}
},

"other_visitors": {
"friendlyBool": {
"enable": 1
},
"friendlyExports": {
"enable": 1,
"regexp": "^require\\.d\\(t, '\"['\"],\\sfunction\\s\\(\\)\\s*\\{\\s+return ([^;]+);\\s+\\}\\)",
"deleteOld": 0
},
"reduceComma": {
"enable": 1,
"support_nest": 0
}
},

"replaceResultString":{
"from": "e.exports = require('electron');",
"to": "//e.exports = require('electron');",
"regexp": 0,
"all": 1
},

"filters": {
"js-beautify": {
"enable": 0,
"break_chained_methods": true
},
"prettier": {
"enable": 1
}
},

"knownPaths": {}
}
`

Always use variable for replaceModules and replaceExports. Because inline for both is not supported fully, most times
e and t would not be replaced.




$3

$3

$3


`
return function(){return m1,m2}, n;
`
but maybe not fully guaranteed because reduceComma change ast during tree travel.
Maybe a better ways is to set multiple visitors for reduceComma
`
"reduceComma": {
"enable": 1,
"support_nest": 0
},
"reduceComma": {
"enable": 1,
"support_nest": 0
}
`

$3

`
require.d(t, 'c', function () {
return F1;
}), require.d(t, 'd', function () {
return F2;
});
`
and at the bottom of a module put following code
`
exports.c = F1;
exports.d = F2;
`
There code allow you jump and refactor in Intellij Idea products.

'"deleteOld": 1' would drop origian code, providing more terse code, but cause errors in the following case
`
r.d(t, "o", function () { return o; });
r.d(t, "setup", function () { return setup; });
let o = 'not ready';
const setup = () => ( o = 'ok' );
`
when this module is exectuted, o==="not ready". but in a real-life app, after setup(), o==="not ready".
If r.d(t, "o", function () { return o; }); is dropped, o is alway equal to "not really".


$3

It would produce new statement require('./bcs1'); from require.bind(null, 'bcs1')

require_visitors works for the node found related with require. This type of visitors can created new code and find and replace require in the new code.




$3

set to 393 when the webpack runtime code in bundle file is like
`
!function (e) {
var t = {};

function r(n) {
if (t[n]) return t[n].exports;
var a = t[n] = {i: n, l: !1, exports: {}};
return e[n].call(a.exports, a, a.exports, r), a.l = !0, a.exports
}

...

r.p = "", r(r.s = 393)
}
`

find other examples here https://github.com/search?q=repo%3Ascil%2Freliable-debundle%20entryPoint&type=code

$3

examples : https://github.com/scil/reliable-debundle/tree/master/test_scil/debundle_result

Update log by scil

1. 2020.07.16 merge from hectorqin/debundle
1. use config.moduleAst = ["body", 0, "expression", "argument", "arguments", 0]; for webpack,
instead of ["body", 0, "expression", "arguments", 0];.
file: src/index.js
2. use recast.types.visit instead of recast.types.traverse.
file: src/extern/replace-method/index.js

2. v0.5.3.1 support windows os dir style using path.normalize.

3. v0.5.3.2 able to parse n.d to require.d

4. v0.5.3.3 support "replaceRequires": "inline", in the situation SameNameVar

5. v0.5.3.4 support "replaceRequires": "inline,variable", and config keepArgumentsDeeperThan

6. v0.5.3.5 support "fileExt":".js".
"1": "tool/str.js" would save n(1) as tool/str.js, not tool/str.js/index.js

7. v0.5.3.6 support "replaceResultString".

8. v0.5.3.7 support friendlyExportsFrom.

9. v0.5.3.8 support friendlyBool.

10. v0.5.3.9 support reduceComma.

11. v0.5.3.10 support filters. used to change produced string. added a new filters prettier.

12. v0.5.3.11 support support_nest.

Efforts to be reliable?

$3

`javascript

function (e, t, n) { // n is require.
n(3); // n is require
function x(){
var n =3; // this n is not require
}
}
`
In old 1egoman/debundle, "replaceRequires": "inline" would replace all n with require in a module function function (e, t ,n). How to limit it?

Reliable-debundle not only support inline or variable, but also both inline and variable which could produce following code:
`
const n = require;
require('./3');
function x(){
var n =3; // this n is not require
}
`

$3

`javascript

function (e, t, n) { // deep: 0
"use strict";
/// n:263
var r;


void 0 === (o = "function" == typeof (r = function () { // deep: 1
}
) ? r.call(t, n, t, e) : r) || (e.exports = o) // n is require as a parameter of a level 1 function

!function () { // deep: 1

r = function () { // deep:2
return d
}.call(t, n, t, e) // n is require, e is module of parameters of a level 2 function

void 0 === r || (e.exports = r) // e is mudule
}()
}
`

By default, scil/debundle only replace the parameter n with level 1 function. To replace n with level 2 function, set
`
"keepArgumentsDeeperThan":2,
`

$3

In old 1egoman/debundle, inline tends to replace all n with require in a module function function (e, t ,n). How to limit it?

#### 3.1. "keepDeeperThan" provided for users

"keepDeeperThan": 2, would make debundle ignore everything in functions with level 3 or deeper.

see examples 8.0 and 8.1 in test_scil/bundle


`javascript
function (e, t, n) { // deep: 0
/// as n(1)

n(0); // this is require

function deep1() { // deep: 1

return function n(param) { // deep: 2

if (param === 0) return 'from the deep2 n, not require n';

return function () { // deep: 3
return n(0) // deep2 n, not require n
}
}
}


var m = deep1()()();

console.log(m);

}
`

#### 3.2. inherent limitation by scil/debundle: SameNameVar

And an extra config "inDescendantsOfSameNameDeclaraton"

When n is require, there may be another varable which is also named n but is not requrie. This is SameNameVar.

`
function (e, t, n) { // ★★★ this n is require
var x = n(0);

function It(e) {
var n = p(e); // ★★★ this n is not require, just a SameNameVar. code: boolVarHasSameName
// Prior to v0.5.3.3(official debundle),
// you have to use "replaceRequires": "variable",,
// otherwise you got require(99) from n(99).
return n && n(99);
}

function b(e, t, n) { // ★★★ this n is not require, just a SameNameVar. code: boolParamHasSameName
return n(99);
}

function c(){ // deep: 1
function n(){} // ★★★ this n is not require, just a SameNameVar. code: boolDeclarationWithSameName
}

function deep1() { // deep: 1

return function n(param) { // deep: 2

if (param === 0) return 'from the deep2 n, not require ';

return function () { // deep: 3
return n(0) // ★★★ deep2 n, not require.
// ★★★ Currently scil/debunble sees it as require,
// but adds a extra config "inDescendantsOfSameNameDeclaraton": "keep",
// or "inDescendantsOfSameNameDeclaraton": "ask",
}
}
}


var m = deep1()()();
}

`

Related Code:
visitFunction and
visitVariableDeclaration in src/extern/replace-method/index.js

Related Test:
3--webpack-SameNameVar-visitVariableDeclaration.js
and 4--webpack-SameNameVar-visitFunction.js in test_scil/bundle

Tools

$3

- https://astexplorer.net/ support multiple parsers
- Esprima parser

$3

- https://github.com/benjamn/recast
- https://github.com/benjamn/ast-types/blob/master/def/core.ts

$3

`
var recast = require('recast');
var print = recast.print;
print(ast_node)
`

Similar projects

- Debundle, V2
- retidy

---

Old debundle doc

Why would I want to debundle my code?

Reasons vary, but this tool was originally developed to help me with a reverse engineering project.
Needless to say, sifting through minified bundles to try and figure out how a service works isn't
fun and is a lot easier when that bundle is broken into files and those files have semantic names.

Configuration

$3

`
{
"type": "browserify",
"entryPoint": 1,
"knownPaths": {}
}
`

(To debundle a simple Webpack bundle, replace browserify the above configuration with webpack)

A configuration can have a number of flags - they are documented in DOCS.md.

FAQ

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No. There a bunch of metadata that's lost when bundling:
- Any custom package.json settings for each node_module and the root package.
- In a webpack bundle, the names of modules aren't in the bundle. By default, debundling will produce
files named after the module id (ie, 1.js) unless manually overridden.
- If your code was minified, the output files from the debundling process will also be minified (ie,
no whitespace, single letter variables, etc). It's up to you to run source through other tools to
make it look nicer.

$3

- Make sure that either when rebundling or running with node that you're using the correct file as
your entrypoint.
- Read through all the configuration options. Some of them have caveats.
- You could have run into an edge case that I haven't seen yet. Feel free to open an issue if you believe that to be the case.

$3

Not officially. However, if a bundle shares the same type module layout as Browserify or Webpack it
may be possible to set the moduleAst
configuration option to point to the location of the modules.




Contributing


- After cloning down the project, run npm install - that should be it.
- Debundler entry point is ./src/index.js (that's how you run it!)
- A bunch of sample bundles are in test_bundles/. A script, test_bundles/run_test.sh can run the
debundler against a given bundle and try to debundle it into dist/. (CI will, as part of running
tests, debundle all the bundles in that folder.)
- Make sure any contribution pass the tests: npm test`

Legal note

Some companies specify in their terms of service that their code cannot be "reverse engineered".
Debundling can definitely (depending on how you're using the code) fall under that umbrella.
Understand what you are doing so you don't break any agreements :smile: