nodejs 文件操作

/** * Created by 26223 on 2016/11/8. */const fs = require('fs');const FileUtils = exports;//写入文件FileUtils.writeFile = function (filePath,data) {    fs.writeFile(filePath, data, function (err) {        if (err) throw err;        console.log('file save successfully '); //文件被保存    });};//读取FileUtils.readFile = function(filePath,encoding){    let length = arguments.length;    if(length<2){        encoding = 'utf-8'    }    fs.readFile(filePath, encoding, function (err, data) {        if (err) throw err;        console.log(data);    });};//复制FileUtils.copyFile = function (srcFile,newFile) {    let readOption = {        flags : 'r',        encoding : null,        mode : 0o666    };    let writeOption = {        flags: 'a',        encoding: null,        mode: 0o666    };    let fileReadStream = fs.createReadStream(srcFile,readOption);    let fileWriteStream = fs.createWriteStream(newFile,writeOption);    /* 1:        fileReadStream.on('data',function(data){            fileWriteStream.write(data);        });        fileReadStream.on('end',function(){            console.log('readStream end');            fileWriteStream.end();        });    */    /**     * 2:     */    fileReadStream.pipe(fileWriteStream);    fileWriteStream.on('close',function(){        console.log('copy over');    });};var result=JSON.parse(fs.readFileSync('config.json'));console.info(result);// FileUtils.copyFile('./PageHelper.js','./newPageHelper.js');