Temporary files and directories


Temporary files, directories, and streams for Node.js.

Handles generating a unique file/directory name under the appropriate system temporary directory, changing the file to an appropriate mode, and supports automatic removal (if asked)

temp has a similar API to the fs module.

Supports v0.10.0+.

Please let me know if you have problems running it on a later version of Node.js or have platform-specific problems.

Install it using npm:

$ npm install temp

Or get it directly from: http://github.com/bruce/node-temp

You can create temporary files with open and openSync, temporary directories with mkdir and mkdirSync, or you can get a unique name in the system temporary directory with path.

Working copies of the following examples can be found under the examples directory.

To create a temporary file use open or openSync, passing them an optional prefix, suffix, or both (see below for details on affixes). The object passed to the callback (or returned) has path and fd keys:

{ path: "/path/to/file",
, fd: theFileDescriptor

In this example we write to a temporary file and call out to grep and wc -l to determine the number of time foo occurs in the text. The temporary file is chmod'd 0600 and cleaned up automatically when the process at exit (because temp.track() is called):

var temp = require('temp'),
    fs   = require('fs'),
    util  = require('util'),
    exec = require('child_process').exec;
// Automatically track and cleanup files at exit 
// Fake data 
var myData = "foo\nbar\nfoo\nbaz";
// Process the data (note: error handling omitted) 
temp.open('myprefix', function(errinfo) {
  if (!err) {
    fs.write(info.fd, myData);
    fs.close(info.fd, function(err) {
      exec("grep foo '" + info.path + "' | wc -l", function(errstdout) {

As noted in the example above, if you want temp to track the files and directories it creates and handle removing those files and directories on exit, you must call track(). The track() function is chainable, and it's recommended that you call it when requiring the module.

var temp = require("temp").track();

Why is this necessary? In pre-0.6 versions of temp, tracking was automatic. While this works great for scripts and Grunt tasks, it's not so great for long-running server processes. Since that's arguably what Node.js is for, you have to opt-in to tracking.

But it's easy.

When tracking, you can run cleanup() and cleanupSync() anytime (cleanupSync() will be run for you on process exit). An object will be returned (or passed to the callback) with cleanup counts and the file/directory tracking lists will be reset.

> temp.cleanupSync();
{ files: 1,
  dirs:  0 }
> temp.cleanup(function(errstats) {
{ files: 1,
  dirs:  0 }

Note: If you're not tracking, an error ("not tracking") will be passed to the callback.

To create a temporary directory, use mkdir or mkdirSync, passing it an optional prefix, suffix, or both (see below for details on affixes).

In this example we create a temporary directory, write to a file within it, call out to an external program to create a PDF, and read the result. While the external process creates a lot of additional files, the temporary directory is removed automatically at exit (because temp.track() is called):

var temp = require('temp'),
    fs   = require('fs'),
    util = require('util'),
    path = require('path'),
    exec = require('child_process').exec;
// Automatically track and cleanup files at exit 
// For use with ConTeXt, http://wiki.contextgarden.net 
var myData = "\\starttext\nHello World\n\\stoptext";
temp.mkdir('pdfcreator', function(errdirPath) {
  var inputPath = path.join(dirPath, 'input.tex')
  fs.writeFile(inputPath, myData, function(err) {
    if (err) throw err;
    exec("texexec '" + inputPath + "'", function(err) {
      if (err) throw err;
      fs.readFile(path.join(dirPath, 'input.pdf'), function(errdata) {
        if (err) throw err;

To create a temporary WriteStream, use 'createWriteStream', which sits on top of fs.createWriteStream. The return value is a fs.WriteStream whose path is registered for removal when temp.cleanup is called (because temp.track() is called).

var temp = require('temp');
// Automatically track and cleanup files at exit 
var stream = temp.createWriteStream();
stream.write("Some data");
// Maybe do some other things 

You can provide custom prefixes and suffixes when creating temporary files and directories. If you provide a string, it is used as the prefix for the temporary name. If you provide an object with prefix, suffix and dir keys, they are used for the temporary name.

Here are some examples:

  • "aprefix": A simple prefix, prepended to the filename; this is shorthand for:
  • {prefix: "aprefix"}: A simple prefix, prepended to the filename
  • {suffix: ".asuffix"}: A suffix, appended to the filename (especially useful when the file needs to be named with specific extension for use with an external program).
  • {prefix: "myprefix", suffix: "mysuffix"}: Customize both affixes
  • {dir: path.join(os.tmpDir(), "myapp")}: default prefix and suffix within a new temporary directory.
  • null: Use the defaults for files and directories (prefixes "f-" and "d-", respectively, no suffixes).

In this simple example we read a pdf, write it to a temporary file with a .pdf extension, and close it.

var fs   = require('fs'),
    temp = require('temp');
fs.readFile('/path/to/source.pdf', function(errdata) {
  temp.open({suffix: '.pdf'}, function(errinfo) {
    if (err) throw err;
    fs.write(info.fd, contents);
    fs.close(info.fd, function(err) {
      if (err) throw err;
      // Do something with the file 

If you just want a unique name in your temporary directory, use path:

var fs = require('fs');
var tempName = temp.path({suffix: '.pdf'});
// Do something with tempName 

Note: The file isn't created for you, and the mode is not changed -- and it will not be removed automatically at exit. If you use path, it's all up to you.

If you want to use the module with Grunt, make sure you use async() in your Gruntfile:

module.exports = function (grunt) {
  var temp = require("temp");
  temp.track(); // Cleanup files, please 
  grunt.registerTask("temptest", "Testing temp", function() {
    var done = this.async(); // Don't forget this! 
    grunt.log.writeln("About to write a file...");
    temp.open('tempfile', function(errinfo) {
      // File writing shenanigans here 
      grunt.log.writeln("Wrote a file!")
      done(); // REALLY don't forget this! 

For more information, see the Grunt FAQ.

$ npm test

You can find the repository at: http://github.com/bruce/node-temp

Issues/Feature Requests can be submitted at: http://github.com/bruce/node-temp/issues

I'd really like to hear your feedback, and I'd love to receive your pull-requests!

Copyright (c) 2010-2014 Bruce Williams. This software is licensed under the MIT License, see LICENSE for details.