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Extracts resources and JavaScript from any installed Electron app (`.asar` bundle), restoring original sources from `.js.map` files when available or formatting minified code with Prettier otherwise.
The skill file stays in the publisher's repository.
Paste the copied command in a terminal. It installs this SKILL.md into that agent.
npx skills add JimLiu/baoyu-skills --skill baoyu-electron-extract -a cursor -y
Extracts resources and JavaScript from any installed Electron app (`.asar` bundle), restoring original sources from `.js.map` files when available or formatting minified code with Prettier otherwise. Use when user wants to "extract Electron app", "decompile Electron", "get the source code of <app>", "inspect app.asar", "看 Electron 应用源码", "提取 .asar", or asks how a desktop Electron app is built. Skips `node_modules` and supports both macOS and Windows.
Extracts resources and JavaScript from any installed Electron app (`.asar` bundle), restoring original sources from `.js.map` files when available or formatting minified code with Prettier otherwise. Use when user wants to "extract Electron app", "decompile Electron", "get the source code of <app>", "inspect app.asar", "看 Electron 应用源码", "提取 .asar", or asks how a desktop Electron app is built. Skips `node_modules` and supports both macOS and Windows.
.asar.js.mapnode_modulesExtracts resources and code from an installed Electron app's app.asar. When a .js.map is present, restores the original source files from the embedded sourcesContent; otherwise formats the minified code with Prettier. Source-map paths are resolved relative to the .js.map file first, so bundled paths like ../../src/main.ts restore to readable paths such as restored/src/main.ts instead of hashed placeholders. Always skips node_modules. Works on macOS and Windows.
When this skill prompts the user, follow this tool-selection rule (priority order):
AskUserQuestion, request_user_input, clarify, ask_user, or any equivalent.Concrete AskUserQuestion references below are examples — substitute the local equivalent in other runtimes.
Scripts in scripts/ subdirectory. {baseDir} = this SKILL.md's directory path. Resolve ${BUN_X} runtime: if bun installed → bun; if npx available → npx -y bun; else suggest installing bun. Replace {baseDir} and ${BUN_X} with actual values.
| Script | Purpose |
|---|---|
scripts/main.ts | App discovery + asar extraction + source-map restoration + Prettier formatting |
Use this skill whenever the user wants to look inside an installed Electron application or inspect its bundled code. Trigger phrases include:
Both app name (e.g., Codex) and absolute path (e.g., /Applications/Codex.app, a .asar file, or a Windows install dir) are accepted. The script handles discovery for both platforms.
1. Determine the input. Ask the user for the app name or path if they haven't given one. If they want a custom output directory, ask for that too.
2. Run the script.
${BUN_X} {baseDir}/scripts/main.ts "<app>" [--output <dir>] [--asar <path>] [--force]
Start with --dry-run first if you're unsure whether discovery will find the right bundle — it prints the resolved paths and exits without touching the filesystem.
3. Handle the result.
AskUserQuestion or the runtime equivalent), then re-run with the chosen absolute path.--force. Ask the user whether to overwrite (--force) or pick a new --output path.--asar /full/path/to/app.asar if the user knows where the bundle lives.4. Point the user at the result. The default output dir is ~/Downloads/<AppName>-electron-extract/. The most interesting subdirectory depends on what was found:
restored/ exists → the original source tree was reconstructed from .js.map files; this is what to read first.extracted/ exists (no maps) → the JS/CSS in extracted/ was Prettier-formatted in place; read from there.The script should preserve original source names and directory structure as much as the source map allows:
sources[] entry with sourceRoot when present, then relative to the .js.map file's directory inside extracted/..vite/main/index.js.map + ../../src/main.ts becomes restored/src/main.ts.extracted/, keep the readable remaining path under restored/ instead of hashing it. For example, .vite/main/index.js.map + ../../../shared/src/lib/foo.ts becomes restored/shared/src/lib/foo.ts.webpack://, file://, and ?loader suffixes.restored/__unknown/<hash>.<ext> only when the source name is empty or cannot be reduced to a safe file path.node_modules and webpack/runtime/* entries; these are bundler/runtime noise, not app sources.# Extract by app name (default output: ~/Downloads/Codex-electron-extract/)
${BUN_X} {baseDir}/scripts/main.ts Codex
# Extract by absolute path (works for .app bundles, install dirs, or .asar files)
${BUN_X} {baseDir}/scripts/main.ts "/Applications/Visual Studio Code.app"
${BUN_X} {baseDir}/scripts/main.ts "C:\Users\you\AppData\Local\Programs\codex"
${BUN_X} {baseDir}/scripts/main.ts --asar /Applications/Codex.app/Contents/Resources/app.asar Codex
# Custom output
${BUN_X} {baseDir}/scripts/main.ts Codex --output ~/work/codex-source
# Preview discovery without writing anything
${BUN_X} {baseDir}/scripts/main.ts Codex --dry-run
# Overwrite an existing output dir
${BUN_X} {baseDir}/scripts/main.ts Codex --force
# Machine-readable result (one JSON line on stdout)
${BUN_X} {baseDir}/scripts/main.ts Codex --json
| Option | Short | Description | Default |
|---|---|---|---|
<app> | App name or absolute path. Required unless --asar is given. | — | |
--output | -o | Output directory | ~/Downloads/<AppName>-electron-extract |
--asar | Override the resolved .asar path | auto-discovered | |
--force | -f | Allow writing into a non-empty existing output dir | false |
--skip-format | Skip Prettier formatting | false | |
--skip-restore | Skip source-map restoration | false | |
--no-unpacked | Don't copy app.asar.unpacked/ alongside | false | |
--dry-run | Print resolved paths and exit without writing | false | |
--json | Emit one JSON-line summary on stdout (suppresses normal output) | false |
~/Downloads/<AppName>-electron-extract/
├── extract-report.json # JSON summary: counts, warnings, resolved paths
├── extracted/ # raw asar contents (JS/CSS Prettier-formatted when no map)
│ └── ... # node_modules left untouched (skipped from format)
├── extracted.unpacked/ # copied from <asar>.unpacked/ if present
│ └── ... # native modules (.node), large assets
└── restored/ # only present if at least one .js.map was usable
└── <original/source/tree> # rebuilt from sourcesContent in each .js.map
.js.map embeds sourcesContent. This is the common case for modern bundlers (webpack, esbuild, Vite, rollup). If a map references external .ts/.js files without embedding them, that map is skipped and the corresponding .js is Prettier-formatted instead. Skipped maps are listed in extract-report.json under warnings.../ segments in source-map paths as automatically unsafe. First resolve them from the map location and then sanitize the final output path so it still stays under restored/. Hash fallback is only for unusable source names./Applications + ~/Applications on macOS, and %LOCALAPPDATA%\Programs, %PROGRAMFILES%, %PROGRAMFILES(X86)%, %APPDATA% on Windows. If discovery finds multiple matches, the script exits and lists them — re-run with an absolute path. On Linux or other platforms, pass --asar /path/to/app.asar explicitly./, the user home directly, or the current working directory, and refuses to populate an existing non-empty output dir without --force.@electron/asar and prettier are resolved on-the-fly via npx -y. First run will be slower while npx caches them.