# javascript-deobfuscator (LostMyCode)

> Browser-based Vue app that restores the strings Obfuscator.io hides behind string-array lookups in JavaScript. The user pastes the obfuscated script and names its string array or decoder function, such as _0x439c; the tool classifies the calls as plain array indexing, a one-argument decoder or a two-argument RC4-style decoder, runs the script's own decoder to replace each call with its string literal, rewrites bracketed property access as dot notation and beautifies the result. The author hosts a demo at deo.sigr.io.

- Type: Tool
- Targets: Website
- Category: Website analysis tools
- Relationship: Foundation tool
- Sources reviewed: 2026-10-20
- Added to the catalog: 2026-11-02
- Original resource: <https://github.com/LostMyCode/javascript-deobfuscator>
- Primary source: <https://github.com/LostMyCode/javascript-deobfuscator/blob/2cc31bf07d9f870ea0871aabf3af5568d165f57d/README.md>
- Catalog page: <https://awesomerea.org/resources/lostmycode-javascript-deobfuscator/>
- Record JSON: <https://awesomerea.org/resources/lostmycode-javascript-deobfuscator/record.json>
- Chinese version: [简体中文](https://awesomerea.org/zh/resources/lostmycode-javascript-deobfuscator/index.md)

## Requirements & limits

- **Prerequisites:** Supply the obfuscated script and identify the target function name yourself; a built-in tip shows call shapes such as _0x439c[103], _0x439c('0x4') and _0x439c('0x2','f]Xg'). The README covers only the Vue CLI 4 project commands (npm install, serve, build and lint), and a GitHub Actions workflow builds the site with Node.js 16 and deploys it to GitHub Pages.
- **Scope:** Unversioned: package.json reports 0.1.0 and marks the package private, there are no GitHub releases or npm package, and the reviewed master commit of 2024-05-31 is the latest push.
- **Limits:** Only these string-array patterns are handled, with a fourth pattern marked experimental, and unrecognized input returns an error. The code has no passes for control-flow flattening, proxy functions, dead code or Obfuscator.io's other transformations, so those remain in the output. Decoding evaluates the pasted script with eval inside a browser web worker, so the input's own code runs; it is not a static AST transformation. The page template also loads js-beautify from cdnjs and a Google Analytics tag.
- **Testing evidence:** The repository has no tests, and the README's only result is an example screenshot.
- **License:** The repository has no license file and GitHub detects no license, so it grants no stated reuse terms.

## Primary sources

1. <https://github.com/LostMyCode/javascript-deobfuscator/blob/2cc31bf07d9f870ea0871aabf3af5568d165f57d/README.md>
2. <https://github.com/LostMyCode/javascript-deobfuscator/blob/2cc31bf07d9f870ea0871aabf3af5568d165f57d/src/xDecoder.js>
3. <https://github.com/LostMyCode/javascript-deobfuscator/blob/2cc31bf07d9f870ea0871aabf3af5568d165f57d/src/Analyzer.js>
4. <https://github.com/LostMyCode/javascript-deobfuscator/blob/2cc31bf07d9f870ea0871aabf3af5568d165f57d/src/components/Main.vue>
5. <https://github.com/LostMyCode/javascript-deobfuscator/blob/2cc31bf07d9f870ea0871aabf3af5568d165f57d/src/components/TargetFuncTip.vue>
6. <https://github.com/LostMyCode/javascript-deobfuscator/blob/2cc31bf07d9f870ea0871aabf3af5568d165f57d/src/worker.js>
7. <https://github.com/LostMyCode/javascript-deobfuscator/blob/2cc31bf07d9f870ea0871aabf3af5568d165f57d/package.json>
8. <https://github.com/LostMyCode/javascript-deobfuscator/blob/2cc31bf07d9f870ea0871aabf3af5568d165f57d/public/index.html>
9. <https://github.com/LostMyCode/javascript-deobfuscator/blob/2cc31bf07d9f870ea0871aabf3af5568d165f57d/.github/workflows/deploy.yml>

## More in Websites

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## About this entry

The description was reviewed against primary sources.
Original editorial content: MIT. Linked projects, papers and assets retain their own rights and licenses.