Simple NodeJS observer. I needed a simple observer which would minify my app.js into app.min.js on saving the file. I'm sure this can be done more efficient, I just needed a small script inside my Javascript folder when developing a client-side app for a client of mine. This observer will minify it using packer (https://github.com/dreamerslab/no…

simple-observer.js

var fs = require("fs");
var forker = require('child_process');

var log = console.log;
log('\nRunning under Node.js version ' + process.versions.node + ' on ' + process.arch +
    '-type processor, ' + process.platform + ' platform.');

var fileName = "app.js";
var fileNameMin = "app.min.js";

log("Watching: " + fileName); 

fs.watch(fileName, {
  persistent: true
}, function(event, filename) {
  log(event + " event occurred on " + filename);
  if (event == "change"){
    log("Packing " + filename + " with packer into " + fileNameMin + ". Just a moment please...");
	  forker.exec('packer -b -i '+filename+' -o '+fileNameMin, function(err, outstr){
  		if (err){
    	  log("ERROR");
      } else {
        log("SUCCESS"); 
      }		  
  	});
  }
});