@dexcalibur/dxc-parser-properties

A TypeScript library for parsing Java-style .properties files with support for comments, multi-line values, escaped characters, and Unicode sequences.

Features

• Parse .properties file format (key-value pairs)
• Support for comments (# and ! prefixes)
• Multi-line value support (backslash continuation)
• Escape sequence handling (\:, \=, \ , etc.)
• Unicode character sequences (\uHHHH)
• Invalid entry detection and reporting
• Zero dependencies
• Full TypeScript support with type definitions

Installation

npm install @dexcalibur/dxc-parser-properties

Usage

import { Properties } from '@dexcalibur/dxc-parser-properties';

// Parse a properties file from a Buffer
const buffer = Buffer.from(`
# Application configuration
version=21.0.1
client=firebase-abt

# Multi-line value
description=This is a long \\
description value
`);

const results = Properties.Parser.fromBuffer(buffer, 0);

// Access parsed properties
console.log(results.ok['version'].value);  // "21.0.1"
console.log(results.ok['client'].value);   // "firebase-abt"

// Check for invalid entries
console.log(results.invalid);  // Array of invalid entries

API Reference

Properties.Parser.fromBuffer(buffer, offset, eol?)

Parses a properties file from a Buffer.

Parameters:

• buffer: Buffer - The buffer containing the properties file content
• offset: number - Starting offset in the buffer (typically 0)
• eol?: string - Optional end-of-line character (defaults to OS-specific EOL)

Returns: Properties.Results

{
  ok: Record<string, Entry>;      // Successfully parsed entries
  invalid: Entry[];                // Invalid entries
}

Properties.Entry

Represents a single property entry:

interface Entry {
  key?: string;         // Property key
  value?: string;       // Property value
  comment?: string;     // Associated comments
  line: number;         // Starting line number
  lineCount: number;    // Number of lines this entry spans
  invalid?: boolean;    // Whether the entry is invalid
}

Properties.Parser.decodeString(encodedStr)

Decodes escape sequences in a property string.

Parameters:

• encodedStr: string - The string with escape sequences

Returns: string - Decoded string

Supports:

• Leading/trailing whitespace removal
• Escaped characters (\:, \=, \ )
• Unicode sequences (\uHHHH)

Properties File Format

The parser supports standard Java .properties file format:

Basic Key-Value Pairs

key=value
another.key:another value

Supported separators: = or :

Comments

# This is a comment
! This is also a comment
key=value

Multi-line Values

long.value=This is a \
multi-line \
value

Escaped Characters

key.with.space=value\ with\ spaces
key.with.separator=value\:with\:colons
unicode.char=\u00FF

Supported Formats

• Format names: properties
• File extensions: .properties
• Format UID: properties_1.0.0

Development

Build

npm run build

Test

npm test

License

This project is licensed under the AGPL-3.0-only License.

Copyright (C) 2026 Reversense SAS

This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, version 3 of the License.

See LICENSE for details.

Repository

• GitHub: reversenseorg/dxc-parser-properties

Part of Reversense Platform

This library is part of the Reversense platform, an automated reverse engineering and analysis platform focused on security, privacy, quality, accessibility, and safety assessment of software, including mobile apps and firmware.