A work in progress, incremental backup script in Node.js

backup.sh

'use strict';

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

const currentDirectory = `${__dirname}/backup-tests/current`;
const backupDirectory = `${__dirname}/backup-tests/backup`;

const getFileHash = (filePath) => {
    const contents = fs.readFileSync(filePath);
    const hash = crypto.createHash('sha1');
    hash.update(contents);
    return hash.digest('hex')
};

const addFileToBackupsQueue = (directory, file, type, hashes) => {
    hashes = hashes || null;

    backupFilesQueue.push({
        path: directory,
        file: file,
        hashes: hashes,
        filePath: `${directory}/${file}`,
        backupType: type
    });
};

const getFilesNeedingBackup = (currentDirectory, backupDirectory) => {
    let files = fs.readdirSync(currentDirectory);

    files.forEach((file) => {
        let stats = fs.lstatSync(`${currentDirectory}/${file}`);

        if (stats.isDirectory()) {
            getFilesNeedingBackup(`${currentDirectory}/${file}`, `${backupDirectory}/${file}`);
            return;
        }

        if (!fs.existsSync(`${backupDirectory}/${file}`)) {
            // File is not backed up, therefor file has to be copied
            // to the backups directory.
            addFileToBackupsQueue(currentDirectory, file, 'full');
            return;
        }

        const currentHash = getFileHash(`${currentDirectory}/${file}`);
        const backupHash = getFileHash(`${backupDirectory}/${file}`);

        if (currentHash !== backupHash) {
            // Hashes are different, therefor file has been
            // modified and needs backing up.
            addFileToBackupsQueue(currentDirectory, file, 'partial', {current: currentHash, backup: backupHash});
        }
    });
};

const backupFilesFromQueue = (backupFilesQueue) => {
    backupFilesQueue.forEach((file) => {
        console.log(JSON.stringify(file, null, 4));
    });

    let total = backupFilesQueue.length;
    let fullTotal = backupFilesQueue.filter(file => file.backupType === 'partial').length;
    let partialTotal = backupFilesQueue.filter(file => file.backupType === 'full').length;

    console.log(`Files needing backup (${total} total):`);
    console.log(`Full: ${partialTotal}/${total}`);
    console.log(`Partial: ${fullTotal}/${total}`);
};

let backupFilesQueue = [];

// This method is recursive and synchronous
getFilesNeedingBackup(currentDirectory, backupDirectory);

// Perform backups from queue
backupFilesFromQueue(backupFilesQueue);