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');