tmp

What is tmp?

The tmp npm package is used for creating temporary files and directories in a Node.js environment. It helps manage and clean up temporary files automatically.

What are tmp's main functionalities?

Temporary File Creation

This feature allows you to create a temporary file. The library provides a callback with the path and file descriptor, and a cleanup callback to remove the file when it's no longer needed.

const tmp = require('tmp');
tmp.file(function _tempFileCreated(err, path, fd, cleanupCallback) {
  if (err) throw err;
  console.log('File: ', path);
  console.log('Filedescriptor: ', fd);
  // If we don't need the file anymore we could manually call the cleanupCallback
  // But that is not necessary if we didn't pass the keep option because the library will clean after itself.
  cleanupCallback();
});

Temporary Directory Creation

This feature allows you to create a temporary directory. Similar to temporary file creation, it provides a path to the directory and a cleanup callback.

const tmp = require('tmp');
tmp.dir(function _tempDirCreated(err, path, cleanupCallback) {
  if (err) throw err;
  console.log('Dir: ', path);
  // Manual cleanup
  cleanupCallback();
});

Synchronous File Creation

This feature allows for synchronous creation of a temporary file name. It returns the name directly without the need for a callback.

const tmp = require('tmp');
const name = tmp.tmpNameSync();
console.log('Temporary filename: ', name);

Synchronous Directory Creation

This feature allows for synchronous creation of a temporary directory. It returns an object with the directory name.

const tmp = require('tmp');
const dir = tmp.dirSync();
console.log('Temporary directory: ', dir.name);

Other packages similar to tmp

temp

The 'temp' package is similar to 'tmp' and is also used for managing temporary files and directories. It provides automatic cleanup and tracking of temporary files, but it has not been updated as frequently as 'tmp'.

tempfile

The 'tempfile' package is a simpler alternative to 'tmp' that focuses on generating temporary file paths. It does not handle the creation or cleanup of the files.

temp-dir

The 'temp-dir' package provides the path to the system's default directory for temporary files, rather than creating temporary files or directories itself.

mktemp

The 'mktemp' package creates temporary files and directories in a way similar to the Unix command of the same name. It offers a lower-level API compared to 'tmp' and requires manual cleanup.

README

Tmp

A simple temporary file and directory creator for node.js.

About

The main difference between bruce's node-temp is that mine more aggressively checks for the existence of the newly created temporary file and creates the new file with O_EXCL instead of simple O_CREAT | O_RDRW, so it is safer.

The API is slightly different as well, Tmp does not yet provide synchronous calls and all the parameters are optional.

You can set whether you want to remove the temporary file on process exit or not, and the destination directory can also be set.

How to install

npm install tmp

Usage

File creation

Simple temporary file creation, the file will be unlinked on process exit.

var tmp = require('tmp');

tmp.file(function _tempFileCreated(err, path, fd) {
  if (err) throw err;

  console.log("File: ", path);
  console.log("Filedescriptor: ", fd);
});

Directory creation

Simple temporary directory creation, it will be removed on process exit.

If the directory still contains items on process exit, then it won't be removed.

var tmp = require('tmp');

tmp.dir(function _tempDirCreated(err, path) {
  if (err) throw err;

  console.log("Dir: ", path);
});

If you want to cleanup the directory even when there are entries in it, then you can pass the unsafeCleanup option when creating it.

Filename generation

It is possible with this library to generate a unique filename in the specified directory.

var tmp = require('tmp');

tmp.tmpName(function _tempNameGenerated(err, path) {
    if (err) throw err;

    console.log("Created temporary filename: ", path);
});

Advanced usage

File creation

Creates a file with mode 0644, prefix will be prefix- and postfix will be .txt.

var tmp = require('tmp');

tmp.file({ mode: 0644, prefix: 'prefix-', postfix: '.txt' }, function _tempFileCreated(err, path, fd) {
  if (err) throw err;

  console.log("File: ", path);
  console.log("Filedescriptor: ", fd);
});

Directory creation

Creates a directory with mode 0755, prefix will be myTmpDir_.

var tmp = require('tmp');

tmp.dir({ mode: 0750, prefix: 'myTmpDir_' }, function _tempDirCreated(err, path) {
  if (err) throw err;

  console.log("Dir: ", path);
});

mkstemps like

Creates a new temporary directory with mode 0700 and filename like /tmp/tmp-nk2J1u.

var tmp = require('tmp');

tmp.dir({ template: '/tmp/tmp-XXXXXX' }, function _tempDirCreated(err, path) {
  if (err) throw err;

  console.log("Dir: ", path);
});

Filename generation

The tmpName() function accepts the prefix, postfix, dir, etc. parameters also:

var tmp = require('tmp');

tmp.tmpName({ template: '/tmp/tmp-XXXXXX' }, function _tempNameGenerated(err, path) {
    if (err) throw err;

    console.log("Created temporary filename: ", path);
});

Graceful cleanup

One may want to cleanup the temporary files even when an uncaught exception occurs. To enforce this, you can call the setGracefulCleanup() method:

var tmp = require('tmp');

tmp.setGracefulCleanup();

Options

All options are optional :)

• mode: the file mode to create with, it fallbacks to 0600 on file creation and 0700 on directory creation
• prefix: the optional prefix, fallbacks to tmp- if not provided
• postfix: the optional postfix, fallbacks to .tmp on file creation
• template: mkstemps like filename template, no default
• dir: the optional temporary directory, fallbacks to system default (guesses from environment)
• tries: how many times should the function try to get a unique filename before giving up, default 3
• keep: signals that the temporary file or directory should not be deleted on exit, default is false, means delete
• unsafeCleanup: recursively removes the created temporary directory, even when it's not empty. default is false