📃 Table of Contents

• Features
• Usage
• API
• Examples
• Changelog
• Support
• License
• Related
• Author

🤖 Features

• ⚡ Counts ad-block rules from strings or files instantly
• 🧠 Ignores comments and metadata for clean totals
• 🧼 Syntax-agnostic - no parser, no dependencies
• 📁 Reads UTF-8 files with a single call
• 🧪 Type-safe - returns exact rule count as number
• 🚫 Throws clear errors for invalid input or missing files
• 🧵 Works with EasyList, AdVoid, and custom filters
• 🧩 Ideal for audits, benchmarks, and list hygiene
• 🐇 Fast - handles tens of thousands of rules in milliseconds
• 🔒 No network, no fetch, no async - pure local logic

🕵🏼 Usage

Install it by executing any of the following, depending on your preferred package manager:

pnpm add @igorskyflyer/adblock-filter-counter

yarn add @igorskyflyer/adblock-filter-counter

npm i @igorskyflyer/adblock-filter-counter

🤹🏼 API

countRules(rules: string): number

Counts ad-block filter rules found in the provided string.

rules - The ad-block filter string to count rules in.

Throws if the input is not a string.
Returns the number of filter rules.

countFileRules(path: PathLike): number

Counts ad-block filter rules found in the provided file.

path - The path to the file that contains the filter rules to count.

Throws if the file cannot be read or is not a valid UTF-8 string.
Returns the number of filter rules.

🗒️ Examples

index.ts

import { countFileRules, countRules } from '@igorskyflyer/adblock-filter-counter'

const total: number = countFileRules('./AdVoid.Full.txt')
console.log(`AdVoid.Full contains ${total} rules.`) // AdVoid.Full contains 7,916 rules.

const raw: string = `
||ads.example.com^
||tracker.net^
! this is a comment
##.ad-banner
`
const count: number = countRules(raw)
console.log(`Inline list contains ${count} rules.`) // Inline list contains 3 rules.

📝 Changelog

📑 Read about the latest changes in the CHANGELOG.

🪪 License

Licensed under the MIT license.

💖 Support

🧬 Related

@igorskyflyer/aria

🧬 Meet Aria, an efficient ad-block filter list compiler, with many features that make your maintenance of ad-block filter lists a breeze! 🦖

@igorskyflyer/adblock-header-extract

✂️ An npm module that provides ways to extract header and metadata from an ad-block filter file. 📃

@igorskyflyer/strip-html

🥞 Removes HTML code from the given string. Can even extract text-only from the given an HTML string. ✨

@igorskyflyer/astro-saferesource

🎐 Adds CSP-compliant inline scripts and styles to Astro! 🎠

@igorskyflyer/astro-easynav-button

🧭 Add an easy-to-use navigational button (jump to top/bottom) to your Astro site. 🔼

👨🏻‍💻 Author

Created by Igor Dimitrijević (@igorskyflyer).