Calculate used localStorage size for a website

console.js

let entries = [];
let totalSize = 0;

// Collect all localStorage entries with their sizes
for (let key in localStorage) {
  if (localStorage.hasOwnProperty(key)) {
    let keySize = new Blob([key]).size; // Size of the key
    let valueSize = new Blob([localStorage[key]]).size; // Size of the value
    let totalEntrySize = keySize + valueSize;
    totalSize += totalEntrySize;
    
    entries.push({
      key: key,
      keySize: keySize,
      valueSize: valueSize,
      totalSize: totalEntrySize
    });
  }
}

// Sort entries by total size (largest first)
entries.sort((a, b) => b.totalSize - a.totalSize);

// Prepare data for table display with formatted sizes
let tableData = entries.map(entry => ({
  Key: entry.key,
  'Total Size (MB)': (entry.totalSize / (1024 * 1024)).toFixed(2),
  'Total Size (KB)': (entry.totalSize / 1024).toFixed(2),
  'Total Size (bytes)': entry.totalSize
}));

// Print entries in table format
console.log('localStorage entries sorted by size (largest first):');
console.table(tableData);

// Print total summary
console.log('---');
console.log(`Total localStorage size: ${totalSize} bytes`);
console.log(`Total size in KB: ${(totalSize / 1024).toFixed(2)} KB`);
console.log(`Total size in MB: ${(totalSize / (1024 * 1024)).toFixed(2)} MB`);