Simple read file system on Node.js, let you know how to prevent checked file tiwce by curr time, prev time. Another is making you know how to get listener from watchFile API

checked_file.js

var fs = require('fs');
var fullpath = '/home/clonn/test.html';

fs.watchFile(fullpath, function (curr, prev) {
    if (curr.mtime.getTime() !== prev.mtime.getTime())
        console.log('file update');
});

checked_files_listen.js

var fs = require('fs');
var fullpath = '/home/clonn/test.html';
var listen = fs.watchFile(fullpath, function (curr, prev) {});
listen.on('change', , function (curr, prev) {
    if (curr.mtime.getTime() !== prev.mtime.getTime())
        console.log('file update');
});

simple_watchfile.js

var fs = require('fs');
var fullpath = '/home/clonn/test.html';

fs.watchFile(fullpath, function (curr, prev) {
    console.log('file update')
});

checked_file.js

make checking files to prevent display log twice by using current time, previous time.

checked_files_listen.js

Get listener from watchFile API, and let people know to using.

simple_watchfile.js

Simple watchFile API. it is simple, but it does not work well.