is-unicode-supported

is-unicode-supported is a lightweight utility library for detecting whether the current terminal environment supports Unicode characters. It provides platform-specific logic to determine Unicode support by checking environment variables and terminal identifiers, making it ideal for command-line tools and CLI applications that need to decide between Unicode symbols and ASCII fallbacks.

Package Information

• Package Name: is-unicode-supported
• Package Type: npm
• Language: JavaScript (ES modules)
• Installation: npm install is-unicode-supported

Core Imports

import isUnicodeSupported from 'is-unicode-supported';

Note: This package is ESM-only and requires Node.js 12+ with ES module support. CommonJS require() is not supported.

Basic Usage

import isUnicodeSupported from 'is-unicode-supported';

const supportsUnicode = isUnicodeSupported();

if (supportsUnicode) {
    console.log('✅ Unicode is supported - using fancy symbols');
} else {
    console.log('[OK] Unicode not supported - using ASCII fallbacks');
}

Capabilities

Unicode Detection

Detects whether the terminal supports Unicode by examining platform-specific environment variables and terminal identifiers.

/**
 * Detect whether the terminal supports Unicode
 * @returns {boolean} true if the terminal supports Unicode, false otherwise
 */
function isUnicodeSupported(): boolean;

Detection Logic:

For non-Windows platforms (macOS, Linux, etc.):

• Returns true by default
• Returns false only if process.env.TERM === 'linux' (Linux console kernel)

For Windows platforms:

• Returns true if any of the following conditions are met:
  • process.env.CI is truthy (CI environments)
  • process.env.WT_SESSION is truthy (Windows Terminal)
  • process.env.TERMINUS_SUBLIME is truthy (Terminus < v0.2.27)
  • process.env.ConEmuTask === '{cmd::Cmder}' (ConEmu and cmder)
  • process.env.TERM_PROGRAM === 'Terminus-Sublime'
  • process.env.TERM_PROGRAM === 'vscode' (VS Code integrated terminal)
  • process.env.TERM === 'xterm-256color'
  • process.env.TERM === 'alacritty'
  • process.env.TERMINAL_EMULATOR === 'JetBrains-JediTerm'
• Returns false if none of the above conditions are met

Usage Examples:

import isUnicodeSupported from 'is-unicode-supported';

// Simple check
if (isUnicodeSupported()) {
    console.log('🎉 Unicode supported!');
} else {
    console.log('Unicode not supported');
}

// CLI output decision
const checkMark = isUnicodeSupported() ? '✅' : '[OK]';
const crossMark = isUnicodeSupported() ? '❌' : '[FAIL]';

console.log(`${checkMark} Test passed`);
console.log(`${crossMark} Test failed`);

// Progress indicators
const spinner = isUnicodeSupported() ? ['⠋', '⠙', '⠹', '⠸', '⠼', '⠴', '⠦', '⠧', '⠇', '⠏'] : ['|', '/', '-', '\\'];

Platform Support

• Node.js: 12+ (ES modules support required)
• Windows: Detects specific terminal environments that support Unicode
• macOS/Linux: Assumes Unicode support except for Linux console kernel
• CI Environments: Automatically detects CI systems that support Unicode

Dependencies

No runtime dependencies. Uses only Node.js built-in modules:

• node:process for platform detection and environment variable access