show-invisibles

🕵️‍♂️ Reveal and clean invisible Unicode characters from text — both as a CLI and a library.

Purpose

Invisible characters like zero-width spaces (U+200B), byte-order marks, or directionality markers can sneak into text files, source code, or user input — often causing frustrating bugs or unexpected behavior.

show-invisibles helps you:

• ✅ Identify and make invisible characters visible in your text.
• 🧹 Clean unwanted or problematic characters.
• ⚒️ Customize how these characters are shown or replaced.
• 🧪 Use as a CLI tool or integrate as a Node.js library.

---

Features

• Supports a wide range of invisible and control characters.
• Offers two main operations:
  • mark: Replaces invisible characters with visible placeholders.
  • clean: Removes or replaces problematic invisible characters.
• Customizable format for marked output: %u (unicode), %n (name), or your own syntax.
• --all flag to show even standard control characters (like \n, \t, \r).
• Emits statistics to stderr (characters found and/or replaced).
• ES Modules support and typings included.

---

Installation

npm install -g show-invisibles

Or use locally in a Node project:

npm install show-invisibles

---

CLI Usage

show-invisibles [file|-] [options]

Options

Flag	Description
--clean	Remove or replace invisible characters (instead of marking them).
--all	Include common control characters like \n, \r, \t.
--format	Format string for replacements (default: [%u]).
--help	Show usage help.

Format String

You can use custom format strings for how invisible characters are displayed:

• %u – Unicode code point (e.g. U+200B)
• %n – Character name (e.g. ZERO_WIDTH_SPACE)
• %% – Literal %

Examples:

# Reveal all invisible characters with default format
cat suspicious.txt | show-invisibles

# Clean all invisibles in a file
show-invisibles --clean suspicious.txt

# Show control chars too, use name instead of code
show-invisibles some.txt --all --format="[%n]"

# Use custom format
show-invisibles --format="!!%u!!" some.txt

---

Library Usage

import {
  markInvisibles,
  cleanInvisibles,
  formatReplacement,
} from 'show-invisibles'

const input = 'Some\u200Btext'
const { result, count } = markInvisibles(input, false, '[%n]')
// result => 'Some[ZERO_WIDTH_SPACE]text'
// count => 1

const cleaned = cleanInvisibles(input)
// cleaned.result => 'Sometext'
// cleaned.count => 1

---

Supported Characters

Includes:

• Zero-width characters (U+200B, U+200C, etc.)
• Directionality markers (U+202A – U+202E, U+2066 – U+2069)
• Byte Order Mark (U+FEFF)
• Figure space (U+2007)
• Control characters (optional): \n, \r, \t, \f, etc.

---

Development

Build

npm run build

Run tests

npm test

---

License

MIT © 2025