🔖 java-remapper

A lightweight JavaScript/TypeScript tool for parsing and applying Java class mappings. It supports multiple mapping formats and allows remapping of Java .class files in the browser or Node.js.

Features

• Supports multiple mapping formats:
  • SRG/XSRG
  • CSRG/TSRG
  • TSRG v2
  • ProGuard
  • Tiny v1
  • Tiny v2
• Automatic format detection based on file content
• Remap .class files from obfuscated to deobfuscated names using mappings
• Works in Node.js and browser environments

Installation

npm install java-remapper

Usage

1. Detect mapping format

import { detectMappingFormat } from "java-remapper";

const content = `
tiny\t2\t0\tnamed
c\texample/ClassName\tcom/example/MyClass
`;
const format = detectMappingFormat(content);
console.log(format); // Output: MappingFormat.TINY2

2. Parse mappings

import { parseMappings, MappingFormat } from "java-remapper";

const mappingsContent = "..."; // Mapping file content
const mappings = parseMappings(MappingFormat.TINY2, mappingsContent);

3. Remap .class files

import { remap } from "java-remapper";
import fs from "fs";

const classBytes = fs.readFileSync("Example.class");
const newBytes = await remap(classBytes, mappings);
fs.writeFileSync("ExampleRemapped.class", newBytes);

4. Types

import { MappingSet } from "java-remapper";

🛠 API

detectMappingFormat(content: string): MappingFormat | null

Detects the mapping format from content.

parseMappings(format: MappingFormat, content: string): MappingSet

Parses a mapping file into a MappingSet.

remap(b: Uint8Array, mappings: MappingSet): Promise<Uint8Array>

Remaps a Java .class file byte array using the given mappings.

Notes

• This library only remaps Java class files, not full JARs. To handle JARs, extract .class files, remap them individually, and repackage.
• Ensure mappings and class files match the same version of obfuscation/deobfuscation.

License

This project is licensed under the MIT License.