index.js

#!/usr/bin/env node

const fs = require('fs');
const chalk = require('chalk');

// Parse command line arguments
const args = process.argv.slice(2);
let minify = false;
let indent = 2;
let validateOnly = false;
let useColor = true;
let inputFile = null;

for (let i = 0; i < args.length; i++) {
  const arg = args[i];
  
  if (arg === '-m' || arg === '--minify') {
    minify = true;
  } else if (arg === '-i' || arg === '--indent') {
    indent = parseInt(args[++i], 10);
  } else if (arg === '-v' || arg === '--validate') {
    validateOnly = true;
  } else if (arg === '--no-color') {
    useColor = false;
  } else if (arg === '-h' || arg === '--help') {
    showHelp();
    process.exit(0);
  } else if (arg === '--version') {
    const pkg = require('./package.json');
    console.log(pkg.version);
    process.exit(0);
  } else if (!arg.startsWith('-')) {
    inputFile = arg;
  }
}

function showHelp() {
  console.log(`
JSON Formatter CLI - Format, validate, and minify JSON

Usage: json-fmt [options] <file>

Options:
  -m, --minify              Minify JSON (remove whitespace)
  -i, --indent <number>     Set indentation spaces (default: 2)
  -v, --validate            Validate JSON without formatting
  --no-color                Disable syntax highlighting
  -h, --help                Show help
  --version                 Show version

Examples:
  json-fmt input.json                    Format JSON file
  echo '{"a":1}' | json-fmt              Format from stdin
  json-fmt --minify input.json           Minify JSON
  json-fmt --indent 4 input.json         Use 4-space indentation
  curl api.com/data | json-fmt           Format API response
`);
}

function colorizeJSON(jsonString) {
  if (!useColor) return jsonString;
  
  return jsonString
    .replace(/"([^"]+)":/g, chalk.blue('"$1"') + ':')
    .replace(/: "([^"]*)"/g, ': ' + chalk.green('"$1"'))
    .replace(/: (\d+\.?\d*)/g, ': ' + chalk.yellow('$1'))
    .replace(/: (true|false)/g, ': ' + chalk.magenta('$1'))
    .replace(/: null/g, ': ' + chalk.gray('null'));
}

function processJSON(input) {
  try {
    const parsed = JSON.parse(input);
    
    if (validateOnly) {
      console.log(chalk.green('✓ Valid JSON'));
      process.exit(0);
    }
    
    let output;
    if (minify) {
      output = JSON.stringify(parsed);
    } else {
      output = JSON.stringify(parsed, null, indent);
    }
    
    console.log(colorizeJSON(output));
    process.exit(0);
    
  } catch (error) {
    console.error(chalk.red('✗ Invalid JSON:'), error.message);
    process.exit(1);
  }
}

// Read input
if (inputFile) {
  if (!fs.existsSync(inputFile)) {
    console.error(chalk.red(`Error: File not found: ${inputFile}`));
    process.exit(1);
  }
  const input = fs.readFileSync(inputFile, 'utf8');
  processJSON(input);
} else {
  // Read from stdin
  let input = '';
  process.stdin.setEncoding('utf8');
  
  process.stdin.on('readable', () => {
    let chunk;
    while ((chunk = process.stdin.read()) !== null) {
      input += chunk;
    }
  });
  
  process.stdin.on('end', () => {
    if (!input.trim()) {
      console.error(chalk.red('Error: No input provided'));
      showHelp();
      process.exit(1);
    }
    processJSON(input);
  });
}