NodeJS：按照不同的操作系统读写文件

var fs = require('fs');
var os = require('os');

var xxx_file = '';
var platform = os.platform();
if (platform.indexOf('win') > -1) {
    xxx_file= 'E:/tmp/xxx_file.txt';
} else if (platform.indexOf('linux') > -1) {
    xxx_file= '/tmp/xxx_file.txt';
}

fs.exists(xxx_file, function(exists) {
    if (exists) {
        fs.readFile(xxx_file, 'utf8', function(err, data) {
                    console.log('____*** content:', data);
                });
        }
});