text-is-upper-case

Is Upper Case

Check if a string is in UPPERCASE format.

Features

• Lightweight - Only ~200B minified + gzipped
• Type-safe - Full TypeScript support with comprehensive type definitions
• Zero dependencies - No external dependencies
• Tree-shakeable - ES modules support
• Universal - Works in browsers, Node.js, and serverless environments
• Well-tested - Comprehensive test suite with edge cases

Installation

# npm
npm install text-is-upper-case

# yarn
yarn add text-is-upper-case

# pnpm
pnpm add text-is-upper-case

# bun
bun add text-is-upper-case

Quick Start

import { isUpperCase } from "text-is-upper-case";

console.log(isUpperCase("HELLO WORLD")); // true
console.log(isUpperCase("Hello World")); // false
console.log(isUpperCase("hello world")); // false

Usage

ES Modules (Recommended)

import { isUpperCase } from "text-is-upper-case";

console.log(isUpperCase("HELLO")); // true

CommonJS

const { isUpperCase } = require("text-is-upper-case");

console.log(isUpperCase("HELLO")); // true

TypeScript

import { isUpperCase } from "text-is-upper-case";

const result: boolean = isUpperCase("HELLO WORLD");
console.log(result); // true

Validation Examples

Basic Validation

import { isUpperCase } from "text-is-upper-case";

// Valid uppercase
isUpperCase("HELLO"); // true
isUpperCase("HELLO WORLD"); // true
isUpperCase("TEST123"); // true
isUpperCase("USER_NAME"); // true
isUpperCase("API-KEY"); // true

// Invalid (not uppercase)
isUpperCase("Hello"); // false
isUpperCase("hello"); // false
isUpperCase("Hello World"); // false
isUpperCase("camelCase"); // false
isUpperCase("PascalCase"); // false

Edge Cases

import { isUpperCase } from "text-is-upper-case";

// Numbers and symbols
isUpperCase("123"); // true
isUpperCase("HELLO123"); // true
isUpperCase("TEST@EMAIL.COM"); // true
isUpperCase("USER_123"); // true

// Empty and whitespace
isUpperCase(""); // true
isUpperCase("   "); // true
isUpperCase("\n\t"); // true

// Special characters
isUpperCase("HELLO-WORLD"); // true
isUpperCase("TEST_CASE"); // true
isUpperCase("FILE.TXT"); // true

Real-World Examples

Environment Variable Validation

import { isUpperCase } from "text-is-upper-case";

function validateEnvVarName(name) {
  if (!isUpperCase(name)) {
    return "Environment variable names should be uppercase";
  }
  return null;
}

console.log(validateEnvVarName("DATABASE_URL")); // null (valid)
console.log(validateEnvVarName("databaseUrl")); // "Environment variable names should be uppercase"

Constant Validation

import { isUpperCase } from "text-is-upper-case";

function validateConstantName(name) {
  if (!isUpperCase(name)) {
    return "Constants should be uppercase";
  }
  return null;
}

console.log(validateConstantName("MAX_RETRIES")); // null
console.log(validateConstantName("maxRetries")); // "Constants should be uppercase"

HTTP Header Validation

import { isUpperCase } from "text-is-upper-case";

function validateHeaderMethod(method) {
  if (!isUpperCase(method)) {
    return "HTTP methods should be uppercase";
  }
  return null;
}

console.log(validateHeaderMethod("GET")); // null
console.log(validateHeaderMethod("get")); // "HTTP methods should be uppercase"

Configuration Validation

import { isUpperCase } from "text-is-upper-case";

function validateConfigConstants(config) {
  const invalidKeys = Object.keys(config).filter(
    (key) => key.startsWith("CONST_") && !isUpperCase(key),
  );

  if (invalidKeys.length > 0) {
    return `Invalid constant keys (must be uppercase): ${invalidKeys.join(", ")}`;
  }
  return null;
}

const config1 = { CONST_MAX_SIZE: 100, normalKey: "value" };
const config2 = { CONST_max_size: 100, normalKey: "value" };

console.log(validateConfigConstants(config1)); // null
console.log(validateConfigConstants(config2)); // "Invalid constant keys..."

API Reference

isUpperCase(input)

Checks if a string is in uppercase format.

Parameters

• input (string): The string to check

Returns

• boolean: true if the string is uppercase, false otherwise

Bundle Size

This package is optimized for minimal bundle size:

• Minified: ~200B
• Gzipped: ~150B
• Tree-shakeable: Yes
• Side effects: None

Browser Support

• Modern browsers: ES2015+ (Chrome 51+, Firefox 54+, Safari 10+)
• Node.js: 12+
• TypeScript: 4.0+
• Bundle formats: UMD, ESM, CommonJS

Testing

# Run tests
pnpm test

# Run tests in watch mode
pnpm test --watch

# Run tests with coverage
pnpm test --coverage

# Type checking
pnpm typecheck

# Linting
pnpm lint

Related Packages

• text-camel-case - Convert to camelCase
• text-capital-case - Convert to Capital Case
• text-constant-case - Convert to CONSTANT_CASE
• text-dot-case - Convert to dot.case
• text-header-case - Convert to Header-Case
• text-case - All case transformations in one package

License

MIT Dmitry Selikhov

Contributing

1. Fork the repository
2. Create your feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add some amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

Support

• Email: selikhov.dmitrey@gmail.com
• Issues: GitHub Issues
• Discussions: GitHub Discussions
• Documentation: Full Documentation

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Made with by Dmitry Selikhov