Check synchronously if file directory exists in Node js

Question

How can I synchronously check  using node js  if a file or directory exists

User · Answer

The path module does not provide a synchronous version of path exists so you have to trick around with the fs module   Fastest thing I can imagine is using fs realpathSync which will throw an error that you have to catch  so you need to make your own wrapper function with a try catch

User · Answer

Using the currently recommended  as of 2015  APIs  per the Node docs   this is what I do   var fs   require  fs     function fileExists filePath        try               return fs statSync filePath  isFile              catch  err                return false            In response to the EPERM issue raised by  broadband in the comments  that brings up a good point   fileExists   is probably not a good way to think about this in many cases  because fileExists   can t really promise a boolean return   You may be able to determine definitively that the file exists or doesn t exist  but you may also get a permissions error   The permissions error doesn t necessarily imply that the file exists  because you could lack permission to the directory containing the file on which you are checking   And of course there is the chance you could encounter some other error in checking for file existence   So my code above is really doesFileExistAndDoIHaveAccessToIt    but your question might be doesFileNotExistAndCouldICreateIt    which would be completely different logic  that would need to account for an EPERM error  among other things      While the fs existsSync answer addresses the question asked here directly  that is often not going to be what you want  you don t just want to know if  something  exists at a path  you probably care about whether the  thing  that exists is a file or a directory    The bottom line is that if you re checking to see if a file exists  you are probably doing that because you intend to take some action based on the result  and that logic  the check and or subsequent action  should accommodate the idea that a thing found at that path may be a file or a directory  and that you may encounter EPERM or other errors in the process of checking

User · Answer

Here is a simple wrapper solution for this   var fs   require  fs   function getFileRealPath s       try  return fs realpathSync s    catch e  return false       Usage    Works for both directories and files If item exists  it returns the path to the file or directory If item does not exist  it returns false   Example   var realPath pathToCheck   lt your dir or file gt   if   realPath getFileRealPath pathToCheck       false       console log  file dir not found    pathToCheck     else       console log  file dir exists    realPath       Make sure you use     operator to test if return equals false  There is no logical reason that fs realpathSync   would return false under proper working conditions so I think this should work 100    I would prefer to see a solution that does not does not generate an Error and resulting performance hit  From an API perspective  fs exists   seems like the most elegant solution

User · Answer

From the answers it appears that there is no official API support for this  as in a direct and explicit check   Many of the answers say to use stat  however they are not strict  We can t assume for example that any error thrown by stat means that something doesn t exist   Lets say we try it with something that doesn t exist     node -e  require  fs   stat  god  err  gt console log err      Error  ENOENT  no such file or directory  stat  god  errno  -2  code   ENOENT   syscall   stat   path   god      Lets try it with something that exists but that we don t have access to     mkdir -p fsm appendage  amp  amp  sudo chmod 0 fsm   node -e  require  fs   stat  fsm appendage  err  gt console log err      Error  EACCES  permission denied  stat  access access  errno  -13  code   EACCES   syscall   stat   path   fsm appendage      At the very least you ll want   let dir exists   async path   gt        let stat      try          stat   await  new Promise              resolve  reject    gt  require  fs   stat path                  err  result    gt  err   reject err    resolve result                        catch e            if e code      ENOENT   return false          throw e             if  stat isDirectory            throw new Error  Not a directory          return true       The question is not clear on if you actually want it to be syncronous or if you only want it to be written as though it is syncronous  This example uses await async so that it is only written syncronously but runs asyncronously   This means you have to call it as such at the top level    async      gt        try           console log await dir exists  god             console log await dir exists  fsm appendage               catch e            console log e                 An alternative is using  then and  catch on the promise returned from the async call if you need it further down   If you want to check if something exists then it s a good practice to also ensure it s the right type of thing such as a directory or file  This is included in the example  If it s not allowed to be a symlink you must use lstat instead of stat as stat will automatically traverse links   You can replace all of the async to sync code in here and use statSync instead  However expect that once async and await become universally supports the Sync calls will become redundant eventually to be depreciated  otherwise you would have to define them everywhere and up the chain just like with async making it really pointless

User · Answer

const fs   require  fs     check in the function like below  if fs existsSync  lt path that need to be checked gt          enter the code to excecute after the folder is there    else       Below code to create the folder  if its not there   fs mkdir   lt folder name gt    cb function

User · Answer

Chances are  if you want to know if a file exists  you plan to require it if it does   function getFile path       try          return require path        catch e           return false

User · Answer

Some answers here says that fs exists and fs existsSync are both deprecated  According to the docs this is no more true  Only fs exists is deprected now      Note that fs exists   is deprecated  but fs existsSync   is not   The   callback parameter to fs exists   accepts parameters that are   inconsistent with other Node js callbacks  fs existsSync   does not   use a callback     So you can safely use fs existsSync   to synchronously check if a file exists

User · Answer

fs exists   is deprecated dont use it  https   nodejs org api fs html fs fs exists path callback  You could implement the core nodejs way used at this  https   github com nodejs node-v0 x-archive blob master lib module js L86  function statPath path      try       return fs statSync path       catch  ex       return false      this will return the stats object then once you ve got the stats object you could try  var exist   statPath   path to your file js    if exist  amp  amp  exist isFile           do something

User · Answer

graph-fs  Install npm i graph-fs   Use const  Node    require  quot graph-fs quot    const directory   new Node  quot  path to directory quot     directory exists      lt --

User · Answer

Using fileSystem  fs  tests will trigger error objects  which you then would need to wrap in a try catch statement  Save yourself some effort  and use a feature introduce in the 0 4 x branch   var path   require  path     var dirs     one    two    three     dirs map function dir      path exists dir  function exists        var message    exists    dir      is a directory    dir      is not a directory       console log message

User · Answer

The documents on fs stat   says to use fs access   if you are not going to manipulate the file   It did not give a justification  might be faster or less memeory use   I use node for linear automation  so I thought I share the function I use to test for file existence   var fs   require  fs     function exists path         Remember file access time will slow your program      try          fs accessSync path         catch  err           return false            return true

User · Answer

Another Update  Needing an answer to this question myself I looked up the node docs  seems you should not be using fs exists  instead use fs open and use outputted error to detect if a file does not exist   from the docs      fs exists   is an anachronism and exists only for historical reasons    There should almost never be a reason to use it in your own code       In particular  checking if a file exists before opening it is an   anti-pattern that leaves you vulnerable to race conditions  another   process may remove the file between the calls to fs exists   and   fs open    Just open the file and handle the error when it s not   there    http   nodejs org api fs html fs fs exists path callback

User · Answer

updated asnwer for those people  correctly  pointing out it doesnt directly answer the question  more bring an alternative option  Sync solution  fs existsSync  filePath   also see docs here   Returns true if the path exists  false otherwise   Async Promise solution In an async context you could just write the async version in sync method with using the await keyword  You can simply turn the async callback method into an promise like this  function fileExists path     return new Promise  resolve  fail    gt  fs access path  fs constants F OK        err  result    gt  err   fail err    resolve result       F OK checks if file is visible  is default does no need to be specified      async function doSomething       var exists   await fileExists  filePath      if exists        console log  file exists           the docs on access

User · Answer

Looking at the source  there s a synchronous version of path exists - path existsSync   Looks like it got missed in the docs   Update   path exists and path existsSync are now deprecated  Please use fs exists and fs existsSync   Update 2016   fs exists and fs existsSync have also been deprecated  Use fs stat   or fs access   instead   Update 2019   use fs existsSync  It s not deprecated   https   nodejs org api fs html fs fs existssync path

User · Answer

The answer to this question has changed over the years  The current answer is here at the top  followed by the various answers over the years in chronological order   Current Answer  You can use fs existsSync     const fs   require  fs       Or  import fs from  fs    with ESM if  fs existsSync path            Do something     It was deprecated for several years  but no longer is  From the docs      Note that fs exists   is deprecated  but fs existsSync   is not   The   callback parameter to fs exists   accepts parameters that are   inconsistent with other Node js callbacks  fs existsSync   does not   use a callback     You ve specifically asked for a synchronous check  but if you can use an asynchronous check instead  usually best with I O   use fs promises access if you re using async functions or fs access  since exists is deprecated  if not   In an async function   try       await fs promises access  somefile           The check succeeded   catch  error           The check failed     Or with a callback   fs access  somefile   error   gt        if   error               The check succeeded       else              The check failed               Historical Answers  Here are the historical answers in chronological order    Original answer from 2010  stat statSync or lstat lstatSync  Update September 2012  exists existsSync  Update February 2015  Noting impending deprecation of exists existsSync  so we re probably back to stat statSync or lstat lstatSync  Update December 2015  There s also fs access path  fs F OK  function        fs accessSync path  fs F OK   but note that if the file directory doesn t exist  it s an error  docs for fs stat recommend using fs access if you need to check for existence without opening  Update December 2016 fs exists   is still deprecated but fs existsSync   is no longer deprecated  So you can safely use it now    Original answer from 2010   You can use statSync or lstatSync  docs link   which give you an fs Stats object  In general  if a synchronous version of a function is available  it will have the same name as the async version with Sync at the end  So statSync is the synchronous version of stat  lstatSync is the synchronous version of lstat  etc   lstatSync tells you both whether something exists  and if so  whether it s a file or a directory  or in some file systems  a symbolic link  block device  character device  etc    e g  if you need to know if it exists and is a directory   var fs   require  fs    try          Query the entry     stats   fs lstatSync   the path            Is it a directory      if  stats isDirectory                 Yes it is         catch  e                      and similarly  if it s a file  there s isFile  if it s a block device  there s isBlockDevice  etc   etc  Note the try catch  it throws an error if the entry doesn t exist at all   If you don t care what the entry is and only want to know whether it exists  you can use path existsSync  or with latest  fs existsSync  as noted by user618408   var path   require  path    if  path existsSync   the path         or fs existsSync                It doesn t require a try catch but gives you no information about what the thing is  just that it s there  path existsSync was deprecated long ago     Side note  You ve expressly asked how to check synchronously  so I ve used the xyzSync versions of the functions above  But wherever possible  with I O  it really is best to avoid synchronous calls  Calls into the I O subsystem take significant time from a CPU s point of view  Note how easy it is to call lstat rather than lstatSync      Is it a directory  lstat   the path   function err  stats        if   err  amp  amp  stats isDirectory                 Yes it is             But if you need the synchronous version  it s there   Update September 2012  The below answer from a couple of years ago is now a bit out of date  The current way is to use fs existsSync to do a synchronous check for file directory existence  or of course  fs exists for an asynchronous check   rather than the path versions below   Example   var fs   require  fs     if  fs existsSync path            Do something       Or  fs exists path  function exists        if  exists               Do something             Update February 2015  And here we are in 2015 and the Node docs now say that fs existsSync  and fs exists   will be deprecated    Because the Node folks think it s dumb to check whether something exists before opening it  which it is  but that s not the only reason for checking whether something exists    So we re probably back to the various stat methods    Until unless this changes yet again  of course   Update December 2015  Don t know how long it s been there  but there s also fs access path  fs F OK         fs accessSync path  fs F OK   And at least as of October 2016  the fs stat documentation recommends using fs access to do existence checks   To check if a file exists without manipulating it afterwards  fs access   is recommended     But note that the access not being available is considered an error  so this would probably be best if you re expecting the file to be accessible   var fs   require  fs     try       fs accessSync path  fs F OK          Do something   catch  e           It isn t accessible       Or  fs access path  fs F OK  function err        if   err               Do something       else              It isn t accessible             Update December 2016  You can use fs existsSync     if  fs existsSync path            Do something     It was deprecated for several years  but no longer is  From the docs      Note that fs exists   is deprecated  but fs existsSync   is not   The   callback parameter to fs exists   accepts parameters that are   inconsistent with other Node js callbacks  fs existsSync   does not   use a callback

User · Answer

I use below function to test if file exists  It catches also other exceptions  So in case there are rights issues e g  chmod ugo-rwx filename or in Windows  Right Click - gt  Properties - gt  Security - gt  Advanced - gt  Permission entries  empty list    function returns exception as it should  The file exists but we don t have rights to access it  It would be wrong to ignore this kinds of exceptions   function fileExists path       try        return fs statSync path  isFile          catch  e         if  e code     ENOENT        no such file or directory  File really does not exist       console log  File does not exist           return false             console log  Exception fs statSync      path           e       throw e     something else went wrong  we don t have rights              Exception output  nodejs errors documentation in case file doesn t exist        Error  ENOENT  no such file or directory  stat  X   delsdfsdf txt     errno  -4058    code   ENOENT     syscall   stat     path   X   delsdfsdf txt      Exception in case we don t have rights to the file  but exists        Error  EPERM  operation not permitted  stat  X  file txt     errno  -4048    code   EPERM     syscall   stat     path   X   file txt

[node.js] Check synchronously if file/directory exists in Node.js

Examples related to node.js

Examples related to fs