isabella232 / node-symlink-or-copy

Symlink files or directories, falling back to copying on Windows

node-symlink-or-copy

Symlink a file or directory to another place. Fall back to copying on Windows. Made for use with Broccoli plugins, for "do what I mean" behavior.

Installation

npm install --save symlink-or-copy

Example

const symlinkOrCopySync = require('symlink-or-copy').sync;

symlinkOrCopySync('src_dir/some_file.txt', 'dest_dir/some_file.txt');
symlinkOrCopySync('src_dir/some_dir', 'dest_dir/some_dir');

Description

symlinkOrCopySync(srcPath, destPath);

Create a symlink at destPath pointing to srcPath.

On Windows, we may fall back to copying srcPath to destPath, preserving last-modified times. However, do not rely on always getting a copy on Windows (see Notes below).

If you pass a relative srcPath, it will be resolved relative to process.cwd(), akin to a copy function. Note that this is unlike fs.symlinkSync, whose srcPath is relative to destPath.

If srcPath does not exist or is a broken symlink, we might throw an exception, or we might create a broken symlink.

When we fall back to copying, symlinks at or beneath srcPath will be dereferenced, and broken symlinks will cause exceptions.

We will throw an exception if destPath already exists. Thus in contrast to Unix cp or ln, the following will fail:

// dest_dir already exists, and we might expect dest_dir/some_dir to be
// created. This does not work; pass 'dest_dir/some_dir' instead.
symlinkOrCopySync('src_dir/some_dir', 'dest_dir');

It is an error if the parent directory of destPath does not already exist.

When we symlink, if the file at srcPath is a symlink as well, it will be dereferenced before symlinking, to avoid runaway symlink indirection.

Notes

• Symlinks technically work on Windows, but they require special rights. For users with those rights, symlinks are used, but when not available, a combination of junctions and copying is used to mimic the behavior somewhat performantly.

• There intentionally isn't an asynchronous version. It's not clear that we need or want one. Before sending a patch to add an async version, please share your use case on the issue tracker.