Gulp - FTP deploy updated files

deploy.json

{
  "env": {
    "staging": {
      "ftpConfig": {
        "host": "xxx",
        "user": "xxx",
        "pass": "xxx"
      },
      "path": {
        "local": "./public",
        "remote": "/www"
      },
      "since": null
    }
  },
  "global": {
    "patterns": [
      "public/**",
      "public/.*",
      "!.editorconfig",
      "!.gitattributes"
    ]
  }
}

gulp.js

/*jscs:enable esnext */
/*jshint esversion: 6 */

var gulp = require('gulp');

// Deploy tools
var ftp = require('vinyl-ftp');
var fs = require('fs');
var vinylFilterSince = require('vinyl-filter-since');

// Variables
var deployConfigFile = './deploy.json';

/**
 * Deploy
 *
 * usage: gulp deploy [--env production]
 * global variables: deployConfigFile, util, console, ftp
 */
gulp.task('deploy', (cb) => {

    var conn;
    var deployConfig = require(deployConfigFile);

    var args = process.argv.slice(3);
    var targetEnv = (args.length && args[0] == '--env') ? args[1] : 'staging';
    var envOptions;

    // Check that environment options exists
    if (!deployConfig.env.hasOwnProperty(targetEnv)) {
        console.error(
            'No config for "%s1" environment.\nAvailable environments are: %a1.'
                .replace('%s1', targetEnv)
                .replace('%a1', Object.keys(deployConfig.env))
        );

        return;
    }

    // envOptions = deployConfig.env[targetEnv];
    envOptions = Object.assign({}, deployConfig.env[targetEnv], deployConfig.global);

    // Configure logger
    if (!envOptions.ftpConfig.hasOwnProperty('log')) {
        envOptions.ftpConfig.log = util.log;
    }

    console.info('Transferring files...\n');

    // Create new connection
    conn = ftp.create(envOptions.ftpConfig);

    gulp.src(envOptions.patterns, {base: envOptions.path.local, buffer: false})
        .pipe(vinylFilterSince(new Date(envOptions.since || 0)))
        .pipe(conn.dest(envOptions.path.remote))
        .on('end', function() {
            console.info('Transfer complete\n');

            // Store timestamp
            deployConfig.env[targetEnv].since = new Date();

            fs.writeFile(deployConfigFile, JSON.stringify(deployConfig, null, 4), cb);
        })
        .on('error', swallowError)
    ;
});