watcher

gulpfile.js

var gulp = require('gulp');
var fs = require('fs');
var join = require('path').join;
var util = require('gulp-util');
var _file = null;
var rootdir = __dirname;
var SRC = null;
const DEST = 'dist';
function writeinfile(file, cb) {
  fs.stat(file, function(err, stats) {
    if (err) return cb(err);
    cb(null, stats);
  })
}

function prepare(file) {
  var absolutePath = join(rootdir, file);
  writeinfile(absolutePath, function(err, stats) {
    if (err) {
      process.exit();
    }
    util.log("'" + util.colors.cyan(file) + "'", util.colors.red(JSON.stringify(stats, null, 2)));
    util.log(util.colors.cyan("'isfile'"), util.colors.magenta(stats.isFile()) );
    util.log(util.colors.cyan("'isDirectory'"), util.colors.magenta(stats.isDirectory()));
    if (stats.isFile()) {
      SRC = file;
      gulp.start('copyProjectFile')
    }
  })
}
/**
 * @link https://www.npmjs.com/package/gulp-chokidar
 */
gulp.task('watch', function() {
  var watch = require('gulp-chokidar');

  watch(['./test/**/*.*', './test/**'], function(event) {

  })
    .on('all', function(eventType) {
      //console.log('all eventtype: ', eventType);
      var text = null;
      switch(eventType) {
        case 'change':
          text = 'was changed';
          break;
        case 'add':
          text = 'was added';
          break;
        case 'delete':
          text = 'was deleted';
          break;
        case 'error':
          text = 'has an error';
          break;
      };

      if(text) {
        util.log("'" + util.colors.cyan(eventType) + "'", text);
      }
    })
    .on('ready', function(test) {
      util.log(util.colors.yellow('multi client is activated'));
    })
    .on('add', function(filepath) {
      prepare(filepath);
    })
    .on('change', function(filepath) {
      prepare(filepath);
    })
    .on('delete', function(filepath) {
      util.log("'" + util.colors.red('deleted') + "'", filepath);
    })
    .on('error', function(err) {
      util.log(util.colors.red(err));
    });
});

gulp.task('copyProjectFile', function (){
  util.log(util.colors.red('copy from'), SRC);
  return gulp.src(SRC).pipe(
    gulp.dest(function(file) {
      console.log(file.base);
      var dest = file.base.replace('/test/', '/'+DEST+'/');
      util.log(util.colors.red('copy to'), dest);
      return dest;
    }));
});

rx-gulpfile.js

'use strict';
let gulp = require('gulp');

let fs = require('fs');
let join = require('path').join;

let chokidar = require('chokidar');
let Rx = require('rxjs');
let util = require('gulp-util');

let rootdir = __dirname;

const DEST = `dist`;

class Project{

  constructor(folder){
    this.path = join(rootdir, folder);
    this.folder = folder;
    this.watcher = chokidar.watch(this.path,{
      persistent: true
    });
  }

  event(type){
    return Rx.Observable.fromEvent(this.watcher, type).delay(500);
  }

  copy(file, folder){
    gulp.src(file).pipe(gulp.dest(
      (file) => {
        // console.log(JSON.stringify(file, null, 2));
        let dest = file.base.replace(`/${folder}/`, `/${DEST}/`);
        this.log(`copy from ${util.colors.white(file.base)} to `, dest, 'cyan', 'yellow');
        return dest;
      }
    ));
  }

  stop(){
    this.watcher.close();
  }

  log(first, second, colorFirst, colorSecond){
    let d = {
      colorFirst: colorFirst||'cyan',
      first: first||'',
      second: second||'',
      colorSecond: colorSecond||'magenta'
    };
    util.log(util.colors[d.colorFirst](d.first), util.colors[d.colorSecond](d.second));
  }

  error(err){
    this.log(err, this.path, 'red');
  }

  complete(){
    this.stop();
    this.log('complete', this.path, 'green');
  }

  add(file){
    this.log(this.folder, file);
    this.copy(file, this.folder);
  }

}

class Client extends Project {

  constructor(folder){
    super(folder);
    this.listener();
  }

  listener(){
    this.event('add').subscribe(
      this.add.bind(this),
      this.error.bind(this),
      this.complete.bind(this)
    );

    this.event('change').subscribe(
      this.add.bind(this),
      this.error.bind(this),
      this.complete.bind(this)
    );
  }
}

class Common extends Project{
  constructor(){
    super(`common`);
    this.listener();
  }

  listener(){
    this.event('add').subscribe(
      this.add.bind(this),
      this.error.bind(this),
      this.complete.bind(this)
    );
     this.event('unlink').subscribe(
      (path) => {
        this.log(`File ${path} has been removed`);
      },
      this.error.bind(this),
      this.complete.bind(this)
    );
    this.event('change').subscribe(
      this.add.bind(this),
      this.error.bind(this),
      this.complete.bind(this)
    );
  }
}

gulp.task('clientStart', () => {
  let common = new Common();
  Rx.Observable.fromEvent(common.watcher, 'ready').subscribe(() => {
    let client = new Client('test');
  });
});