React Native Decompiler [ALPHA]

Note that the NPM package react-native-decompiler while based off this repo is maintained by someone else.

DOES NOT SUPPORT HERMES/BINARY (FACEBOOK, INSTAGRAM) REACT NATIVE BUNDLES

DOES NOT SUPPORT WEBPACK V5 BUNDLES

Decompiles React Native index.android.bundle JS files. Webpack files too!

Also tries to remove some compilation artifacts (via internal plugins, ESLint, and Prettier) to make it easier to read.

Usage

1. Download
2. npm start -- <ARGUMENTS> (the -- is very important!)

Example command: npm start -- -i index.android.bundle -o ./output

Command params:

• -i (required) - input file/folder
• -o (required) - the path to the output folder
• -e - a module ID, if specified will only decompile that module & it's dependencies.
• -p - performance monitoring flag, will print out runtime for each decompiler plugin
• -v - verbose flag, does not include debug logging (use DEBUG=react-native-decompiler:* env flag for that)
• --es6 - attempts to decompile to ES6 module syntax.
• --noEslint - does not run ESLint after doing decompilation
• --noPrettier - does not run Prettier after doing decompilation
• --unpackOnly - only unpacks the app with no other adjustments
• --decompileIgnored - decompile ignored modules (modules are generally ignored if they are flagged as an NPM module)
• --agressiveCache - skips some cache checks at the expense of possible cache desync
• --noProgress - don't show progress bar
• --debug - when also given a module ID, will print out that modules code after any plugin handles the app.

Valid inputs

The following input formats are currently supported:

• A single index.android.bundle file that contains all modules (most cases for React Native)
• A folder containing React Native modules (usually called js-modules) in "unbundled" apps
• A single Webpack V4 (V5 not supported) entrypoint bundle file (entrypoint bundles begin with !function(e), chunked bundles start with window.webpackJsonp).
• A folder containg Webpack V4 (V5 not supported) chunks, where at least one file is the entrypoint

Troubleshooting

Out of memory errors

Some files are big enough that Node will run out of memory. You can try disabling various features that might be memory intensive. For example, try the -e, --noEslint, --noPrettier, --unpackOnly flags.

Another option is to give Node more memory. Here is an example command (run this instead of npm start): node -r ts-node/register --max-old-space-size=<MEMORY IN MB> ./src/main.ts <ARGUMENTS>.

Extending

The decompiler operates on a tagger -> editor -> decompiler system.

• Taggers - Manipulates the module metadata
• Editors - Manipulates the module lines (add, move, or remove).
• Decompilers - Manipulates the module code.

To add a new plugin, add it into the represpective list.

The plugins are initialized per module, so any data you store in your plugins will only persist for the current module.

If your plugin needs to be run before or after other plugins, adjust the ordering in the list, or modify it's pass position.

Guidelines:

• When doing any modifications to the AST, use the NodePath methods.
• When you are only doing reading, directly reading from .node is acceptable.