This chapter presents you with a challenge: creating an advanced console app named DirInspect Pro. This app will empower you to thoroughly analyze any directory and gain insightful statistics about its files and subdirectories.

Challenge

Picture a scenario where you must navigate a labyrinth of folders containing crucial files and data. DirInspect Pro is your ally in this journey, providing comprehensive insights into the directory's structure and contents.

The Resulting App

Get ready to wield DirInspect Pro's capabilities. The app will furnish you with critical information, such as

• The total number of items;
• The aggregate size of all items;
• The largest file's name and size;
• The detailed list of individual file names and sizes.

Two Paths to Choose

You have two paths ahead.

• The first is to tackle this challenge head-on, honing your skills without guidance;
• The second is to follow a helpful guide that guarantees your success.

Whichever path you choose, you're in for a rewarding journey culminating in creating a captivating and functional console app.

Masterplan

• Step 1: Import Required Modules;
• Step 2: Define getStats Function;
• Step 3: Define analyzeFile Function;
• Step 4: Define analyzeDirectory Function;
• Step 5: Define main Function and Invoke;
• Conclusion;
• Full App Code.

Step 1: Import Required Modules

To embark on this adventure, you'll need the right tools. Begin by importing two key modules: fs.promises to manage the file system asynchronously and path to handle file paths effectively.

const fs = require("fs").promises;
const path = require("path");

Step 2: Define getStats Function

The asynchronous function, getStats, takes a file or directory path as an argument and attempts to retrieve its statistics using fs.stat.

• If successful, it returns the statistics;
• If an error occurs, it logs an error message and returns null.

async function getStats(filePath) {
  try {
    const stats = await fs.stat(filePath);
    return stats;
  } catch (err) {
    console.error("Error getting stats:", err.message);
    return null;
  }
}

Step 3: Define analyzeFile Function

The analyzeFile function uses the getStats function to obtain statistics for a file. If statistics are available (not null), it returns an object containing the file's name (extracted using path.basename) and its size.

async function analyzeFile(filePath) {
  const stats = await getStats(filePath);
  if (!stats) return null;

  return {
    name: path.basename(filePath),
    size: stats.size,
  };
}

Step 4: Define analyzeDirectory Function

The analyzeDirectory function scans a directory and gathers full statistics about its contents. How it works: it reads all items inside the directory using fs.readdir. For each item:

• Builds the full path with path.join;
• Uses getStats to detect whether it's a file or a folder;
• If it's a file:
  • Calls analyzeFile to get { name, size };
  • Updates totals, largest file, and the file list.
• If it's a directory:
  • Recursively calls analyzeDirectory;
  • Merges results into the current statistics.

async function analyzeDirectory(directoryPath) {
  let totalItems = 0;
  let totalFiles = 0;
  let totalSize = 0;
  let largestFile = { name: "", size: 0 };
  let fileList = [];

  try {
    const items = await fs.readdir(directoryPath);

    for (const item of items) {
      const itemPath = path.join(directoryPath, item);
      const stats = await getStats(itemPath);
      if (!stats) continue;

      totalItems++;

      if (stats.isFile()) {
        const fileInfo = await analyzeFile(itemPath);
        if (!fileInfo) continue;

        totalFiles++;
        totalSize += fileInfo.size;

        if (fileInfo.size > largestFile.size) {
          largestFile = fileInfo;
        }

        fileList.push(fileInfo);
      } else if (stats.isDirectory()) {
        const subDirectoryStats = await analyzeDirectory(itemPath);

        totalItems += subDirectoryStats.totalItems;
        totalFiles += subDirectoryStats.totalFiles;
        totalSize += subDirectoryStats.totalSize;

        if (subDirectoryStats.largestFile.size > largestFile.size) {
          largestFile = subDirectoryStats.largestFile;
        }

        fileList = fileList.concat(subDirectoryStats.fileList);
      }
    }

    return {
      totalItems,
      totalFiles,
      totalSize,
      largestFile,
      fileList
    };
  } catch (err) {
    console.error("Error analyzing directory contents:", err.message);
    return {
      totalItems: 0,
      totalFiles: 0,
      totalSize: 0,
      largestFile: { name: "", size: 0 },
      fileList: []
    };
  }
}

Step 5: Define main Function and Invoke

The main function is the entry point of the script. It specifies the directory path to analyze (in this case, ./docs), calls the analyzeDirectory function to obtain the statistics of the directory and its contents, and then outputs the collected information. The function prints out

• The total number of items;
• The total number of files;
• The total size;
• The details about the largest file;
• The list of files in the directory.

async function main() {
  const directoryPath = "./docs";
  const directoryStats = await analyzeDirectory(directoryPath);

  console.log("Directory Analysis:");
  console.log("Total items:", directoryStats.totalItems);
  console.log("Total files:", directoryStats.totalFiles);
  console.log("Total size (bytes):", directoryStats.totalSize);
  console.log(
    "Largest file:",
    directoryStats.largestFile.name,
    "Size:",
    directoryStats.largestFile.size,
    "bytes"
  );

  console.log("\nFile List:");
  for (const file of directoryStats.fileList) {
    console.log(file.name, "Size:", file.size, "bytes");
  }
}

main();

Full App Code

const fs = require("fs").promises;
const path = require("path");

async function getStats(filePath) {
  try {
    const stats = await fs.stat(filePath);
    return stats;
  } catch (err) {
    console.error("Error getting stats:", err.message);
    return null;
  }
}

async function analyzeFile(filePath) {
  const stats = await getStats(filePath);
  if (!stats) return null;

  return {
    name: path.basename(filePath),
    size: stats.size
  };
}

async function analyzeDirectory(directoryPath) {
  let totalItems = 0;
  let totalFiles = 0;
  let totalSize = 0;
  let largestFile = { name: "", size: 0 };
  let fileList = [];

  try {
    const items = await fs.readdir(directoryPath);

    for (const item of items) {
      const itemPath = path.join(directoryPath, item);
      const stats = await getStats(itemPath);
      if (!stats) continue;

      totalItems++;

      if (stats.isFile()) {
        const fileInfo = await analyzeFile(itemPath);
        if (!fileInfo) continue;

        totalFiles++;
        totalSize += fileInfo.size;

        if (fileInfo.size > largestFile.size) {
          largestFile = fileInfo;
        }

        fileList.push(fileInfo);
      } else if (stats.isDirectory()) {
        const subDirectoryStats = await analyzeDirectory(itemPath);

        totalItems += subDirectoryStats.totalItems;
        totalFiles += subDirectoryStats.totalFiles;
        totalSize += subDirectoryStats.totalSize;

        if (subDirectoryStats.largestFile.size > largestFile.size) {
          largestFile = subDirectoryStats.largestFile;
        }

        fileList = fileList.concat(subDirectoryStats.fileList);
      }
    }

    return {
      totalItems,
      totalFiles,
      totalSize,
      largestFile,
      fileList
    };
  } catch (err) {
    console.error("Error analyzing directory contents:", err.message);
    return {
      totalItems: 0,
      totalFiles: 0,
      totalSize: 0,
      largestFile: { name: "", size: 0 },
      fileList: []
    };
  }
}

async function main() {
  const directoryPath = "./docs";
  const directoryStats = await analyzeDirectory(directoryPath);

  console.log("Directory Analysis:");
  console.log("Total items:", directoryStats.totalItems);
  console.log("Total files:", directoryStats.totalFiles);
  console.log("Total size (bytes):", directoryStats.totalSize);

  console.log(
    "Largest file:",
    directoryStats.largestFile.name,
    "Size:",
    directoryStats.largestFile.size,
    "bytes"
  );

  console.log("\nFile List:");
  for (const file of directoryStats.fileList) {
    console.log(file.name, "Size:", file.size, "bytes");
  }
}

main();