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sync后缀的方法为同步方法，不具有sync后缀的方法为异步方法。fs.readFile(path[, options], callback)
fs.readFileSync(path[, options])
fs.writeFile(file, data[, options], callback)
let fs = require('fs');fs.writeFile('./1.txt',Date.now()+'\n',{flag:'a'},function(){ console.log('ok');}); fs.writeFileSync(file, data[, options])
fs.appendFile(file, data[, options], callback)
fs.appendFile('./1.txt',Date.now()+'\n',function(){ console.log('ok');}) function copy(src,target){ fs.readFile(src,function(err,data){ fs.writeFile(target,data); })} fs.open(filename,flags,[mode],callback);
- FileDescriptor 是文件描述符
- FileDescriptor 可以被用来表示文件
- in -- 标准输入(键盘)的描述符
- out -- 标准输出(屏幕)的描述符
- err -- 标准错误输出(屏幕)的描述符
fs.open('./1,txt','r',0600,function(err,fd){}); fs.read(fd, buffer, offset, length, position, callback((err, bytesRead, buffer)))
//珠峰培训const fs=require('fs');const path=require('path');fs.open(path.join(__dirname,'1.txt'),'r',0o666,function (err,fd) { console.log(err); let buf = Buffer.alloc(6); fs.read(fd,buf,0,6,3,function(err, bytesRead, buffer){ console.log(bytesRead);//6 console.log(buffer===buf);//true console.log(buf.toString());//峰培 })}) fs.write(fd, buffer[, offset[, length[, position]]], callback)
const fs=require('fs');const path=require('path');fs.open(path.join(__dirname,'1.txt'),'w',0o666,function (err,fd) { console.log(err); let buf=Buffer.from('珠峰培训'); fs.write(fd,buf,3,6,0,function(err, bytesWritten, buffer){ console.log(bytesWritten);//6 console.log(buffer===buf);//true console.log(buf.toString());//珠峰培训 })}) fs.fsync(fd,[callback]);
fs.close(fd,[callback]);
let buf = Buffer.from('珠峰培训');fs.open('./2.txt', 'w', function (err, fd) { fs.write(fd, buf, 3, 6, 0, function (err, written, buffer) { console.log(written); fs.fsync(fd, function (err) { fs.close(fd, function (err) { console.log('写入完毕!') } ); }); })}); let BUFFER_SIZE=1;const path=require('path');const fs=require('fs');function copy(src,dest,callback) { let buf=Buffer.alloc(BUFFER_SIZE); fs.open(src,'r',(err,readFd)=>{ fs.open(dest,'w',(err,writeFd) => { !function read() { fs.read(readFd,buf,0,BUFFER_SIZE,null,(err,bytesRead) => { bytesRead&&fs.write(writeFd,buf,0,bytesRead,read); }); }() }) });}copy(path.join(__dirname,'1.txt'),path.join(__dirname,'2.txt'),()=>console.log('ok')); fs.mkdir(path[, mode], callback)
要求父目录必须存在
fs.access(path[, mode], callback)
fs.access('/etc/passwd', fs.constants.R_OK | fs.constants.W_OK, (err) => { console.log(err ? 'no access!' : 'can read/write');});
fs.readdir(path[, options], callback)
fs.stat(path, callback)
fs.rename(oldPath, newPath, callback)
fs.unlink(path, callback)
fs.ftruncate(fd[, len], callback)
const fd = fs.openSync('temp.txt', 'r+');// 截断文件至前4个字节fs.ftruncate(fd, 4, (err) => { console.log(fs.readFileSync('temp.txt', 'utf8'));}); fs.watchFile(filename[, options], listener)
let fs = require('fs');fs.watchFile('1.txt', (curr, prev) => { //parse() 方法可解析一个日期时间字符串，并返回 1970/1/1 午夜距离该日期时间的毫秒数。 if(Date.parse(prev.ctime)==0){ console.log('创建'); }else if(Date.parse(curr.ctime)==0){ console.log('删除'); }else if(Date.parse(prev.ctime) != Date.parse(curr.ctime)){ console.log('修改'); }}); let fs=require('fs');let path=require('path');function makepSync(dir) { let parts=dir.split(path.sep); for (let i=1;i<=parts.length;i++){ let parent=parts.slice(0,i).join(path.sep); try { fs.accessSync(parent); } catch (error) { fs.mkdirSync(parent); } }} function makepAsync(dir,callback) { let parts=dir.split(path.sep); let i=1; function next() { if (i>parts.length) return callback&&callback(); let parent=parts.slice(0,i++).join(path.sep); fs.access(parent,err => { if (err) { fs.mkdir(parent,next); } else { next(); } }); } next();} async function mkdir(parent) { return new Promise((resolve,reject) => { fs.mkdir(parent,err => { if (err) reject(err); else resolve(); }); });}async function access(parent) { return new Promise((resolve,reject) => { fs.access(parent,err => { if (err) reject(err); else resolve(); }); });}async function makepPromise(dir,callback) { let parts=dir.split(path.sep); for (let i=1;i<=parts.length;i++){ let parent=parts.slice(0,i).join(path.sep); try { await access(parent); }catch(err) { await mkdir(parent); } }} let fs=require('fs');let path=require('path')function rmSync(dir) { try { let stat = fs.statSync(dir); if (stat.isFile()) { fs.unlinkSync(dir); } else { let files=fs.readdirSync(dir); files .map(file => path.join(dir,file)) .forEach(item=>rmSync(item)); fs.rmdirSync(dir); } } catch (e) { console.log('删除失败!'); }}rmSync(path.join(__dirname,'a')); function rmPromise(dir) { return new Promise((resolve,reject) => { fs.stat(dir,(err,stat) => { if (err) return reject(err); if (stat.isDirectory()) { fs.readdir(dir,(err,files) => { let paths = files.map(file => path.join(dir,file)); let promises = paths.map(p=>rmPromise(p)); Promise.all(promises).then((() => fs.rmdir(dir,resolve))); }); } else { fs.unlink(dir,resolve); } }); });}rmPromise(path.join(__dirname,'a')).then(() => { console.log('删除成功');}) function rmAsyncSeries(dir,callback) { setTimeout(() => { fs.stat(dir,(err,stat) => { if (err) return callback(err); if (stat.isDirectory()) { fs.readdir(dir,(err,files) => { let paths = files.map(file => path.join(dir,file)); function next(index) { if (index>=files.length) return fs.rmdir(dir,callback); let current=paths[index]; rmAsyncSeries(current,()=>next(index+1)); } next(0); }); } else { fs.unlink(dir,callback); } }) },1000);}console.time('cost');rmAsyncSeries(path.join(__dirname,'a'),err => { console.timeEnd('cost');}) function rmAsyncParallel(dir,callback) { setTimeout(() => { fs.stat(dir,(err,stat) => { if (err) return callback(err); if (stat.isDirectory()) { fs.readdir(dir,(err,files) => { let paths=files.map(file => path.join(dir,file)); if (paths.length>0) { let i=0; function done() { if (++i == paths.length) { fs.rmdir(dir,callback); } } paths.forEach(p=>rmAsyncParallel(p,done)); } else { fs.rmdir(dir,callback); } }); } else { fs.unlink(dir,callback); } }) },1000);}console.time('cost');rmAsyncParallel(path.join(__dirname,'a'),err => { console.timeEnd('cost');}) function rmSync(dir){ let arr=[dir]; let index=0; while (arr[index]) { let current=arr[index++]; let stat=fs.statSync(current); if (stat.isDirectory()) { let dirs=fs.readdirSync(current); arr=[...arr,...dirs.map(d => path.join(current,d))]; } } let item; while (null != (item = arr.pop())) { let stat = fs.statSync(item); if (stat.isDirectory()) { fs.rmdirSync(item); } else { fs.unlinkSync(item); } }} function rmdirWideAsync(dir,callback){ let dirs=[dir]; let index=0; function rmdir() { let current = dirs.pop(); if (current) { fs.stat(current,(err,stat) => { if (stat.isDirectory()) { fs.rmdir(current,rmdir); } else { fs.unlink(current,rmdir); } }); } } !function next() { let current=dirs[index++]; if (current) { fs.stat(current,(err,stat) => { if (err) callback(err); if (stat.isDirectory()) { fs.readdir(current,(err,files) => { dirs=[...dirs,...files.map(item => path.join(current,item))]; next(); }); } else { next(); } }); } else { rmdir(); } }();} A / \ B C / \ \ D E F
function deepSync(dir){ console.log(dir); fs.readdirSync(dir).forEach(file=>{ let child = path.join(dir,file); let stat = fs.statSync(child); if(stat.isDirectory()){ deepSync(child); }else{ console.log(child); } });} function deep(dir,callback) { console.log(dir); fs.readdir(dir,(err,files)=>{ !function next(index){ if(index == files.length){ return callback(); } let child = path.join(dir,files[index]); fs.stat(child,(err,stat)=>{ if(stat.isDirectory()){ deep(child,()=>next(index+1)); }else{ console.log(child); next(index+1); } }) }(0) })} function wideSync(dir){ let dirs = [dir]; while(dirs.length>0){ let current = dirs.shift(); console.log(current); let stat = fs.statSync(current); if(stat.isDirectory()){ let files = fs.readdirSync(current); files.forEach(item=>{ dirs.push(path.join(current,item)); }); } }} // 异步广度遍历function wide(dir, cb) { console.log(dir); cb && cb() fs.readdir(dir, (err, files) => { !function next(i){ if(i>= files.length) return; let child = path.join(dir,files[i]); fs.stat(child,(err,stat)=>{ if(stat.isDirectory()){ wide(child, () => next(i+1)); } else { console.log(child); next(i+1); } }) }(0); })}wide(path.join(__dirname,'a')); path是node中专门处理路径的一个核心模块
var path = require('path');var fs = require('fs');/** * normalize 将非标准化的路径转化成标准化的路径 * 1.解析. 和 .. * 2.多个斜杠会转成一个斜杠 * 3.window下的斜杠会转成正斜杠 * 4.如果以斜杠会保留 **/console.log(path.normalize('./ab//..\\c//e//..//'));// \a\c\//多个参数字符串合并成一个路径 字符串console.log(path.join(__dirname,'a','b'));/** * resolve * 以就用程序为根目录，做为起点，根据参数解析出一个绝对路径 * 1.以应用程序为根起点 * 2... . * 3. 普通 字符串代表子目录 * 4. /代表绝地路径根目录 */console.log(path.resolve());//空代表当前的目录 路径console.log(path.resolve('a','/c'));// /a/b// d:\c//可以获取两个路径之间的相对关系console.log(path.relative(__dirname,'/a'));// a//返回指定路径的所在目录console.log(path.dirname(__filename)); // 9.pathconsole.log(path.dirname('./1.path.js'));// 9.path//basename 获取路径中的文件名console.log(path.basename(__filename));console.log(path.basename(__filename,'.js'));console.log(path.extname(__filename));console.log(path.sep);//文件分隔符 window \ linux /console.log(path.win32.sep);console.log(path.posix.sep);console.log(path.delimiter);//路径 分隔符 window ; linux : | 符号 | 含义 |
|---|---|
| r | 读文件，文件不存在报错 |
| r+ | 读取并写入，文件不存在报错 |
| rs | 同步读取文件并忽略缓存 |
| w | 写入文件，不存在则创建，存在则清空 |
| wx | 排它写入文件 |
| w+ | 读取并写入文件，不存在则创建，存在则清空 |
| wx+ | 和w+类似，排他方式打开 |
| a | 追加写入 |
| ax | 与a类似，排他方式写入 |
| a+ | 读取并追加写入，不存在则创建 |
| ax+ | 作用与a+类似，但是以排他方式打开文件 |
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