From e0b4988bb4a3c864914e73335c3c3074c0b399d9 Mon Sep 17 00:00:00 2001
From: Zoltan Kochan <z@kochan.io>
Date: Sun, 20 Nov 2022 18:45:38 +0200
Subject: [PATCH] feat: overwrite option

---
 LICENSE       |  2 +-
 README.md     |  6 +++++-
 src/index.ts  |  9 ++++++---
 test/index.ts | 35 +++++++++++++++++++++++++++++++++++
 4 files changed, 47 insertions(+), 5 deletions(-)

diff --git a/LICENSE b/LICENSE
index fd1be1d..9e504a2 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,6 +1,6 @@
 The MIT License (MIT)
 
-Copyright (c) 2016-2021 Zoltan Kochan <z@kochan.io>
+Copyright (c) 2016-2022 Zoltan Kochan <z@kochan.io>
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/README.md b/README.md
index b77997d..226638b 100644
--- a/README.md
+++ b/README.md
@@ -49,10 +49,14 @@ symlinkDir('src', 'node_modules/src')
 
 ## API
 
-### `symlinkDir(src, dest): Promise<{ reused: boolean, warn?: string }>`
+### `symlinkDir(src, dest, opts?): Promise<{ reused: boolean, warn?: string }>`
 
 Creates a symlink in `dest` that points to `src`.
 
+Options:
+
+* `overwrite` - *boolean* - is `true` by default. When `false`, existing files at dest are not overwritten.
+
 Result:
 
 * `reused` - *boolean* - is `true` if the symlink already existed pointing to the `src`.
diff --git a/src/index.ts b/src/index.ts
index 9a1f6d2..43a2d72 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -19,7 +19,7 @@ function resolveSrcOnNonWin (src: string, dest: string) {
   return path.relative(path.dirname(dest), src)
 }
 
-function symlinkDir (src: string, dest: string): Promise<{ reused: Boolean, warn?: string }> {
+function symlinkDir (src: string, dest: string, opts?: { overwrite?: boolean }): Promise<{ reused: Boolean, warn?: string }> {
   dest = betterPathResolve(dest)
   src = betterPathResolve(src)
 
@@ -27,14 +27,14 @@ function symlinkDir (src: string, dest: string): Promise<{ reused: Boolean, warn
 
   src = resolveSrc(src, dest)
 
-  return forceSymlink(src, dest)
+  return forceSymlink(src, dest, opts)
 }
 
 /**
  * Creates a symlink. Re-link if a symlink already exists at the supplied
  * srcPath. API compatible with [`fs#symlink`](https://nodejs.org/api/fs.html#fs_fs_symlink_srcpath_dstpath_type_callback).
  */
-async function forceSymlink (src: string, dest: string): Promise<{ reused: Boolean, warn?: string }> {
+async function forceSymlink (src: string, dest: string, opts?: { overwrite?: boolean }): Promise<{ reused: Boolean, warn?: string }> {
   try {
     await fs.symlink(src, dest, symlinkType)
     return { reused: false }
@@ -53,6 +53,9 @@ async function forceSymlink (src: string, dest: string): Promise<{ reused: Boole
         return { reused: false }
       case 'EEXIST':
       case 'EISDIR':
+        if (opts?.overwrite === false) {
+          throw err
+        }
         // If the target file already exists then we proceed.
         // Additional checks are done below.
         break
diff --git a/test/index.ts b/test/index.ts
index ab5daa4..764a05b 100644
--- a/test/index.ts
+++ b/test/index.ts
@@ -21,6 +21,25 @@ test('rename target folder if it exists', async (t) => {
   t.end()
 })
 
+test('do not rename target folder if overwrite is set to false', async (t) => {
+  const temp = tempy.directory()
+  t.comment(`testing in ${temp}`)
+  process.chdir(temp)
+
+  await fs.mkdir('src')
+  await fs.mkdir('dest')
+
+  let err!: Error
+  try {
+    await symlink('src', 'dest', { overwrite: false })
+  } catch (_err) {
+    err = _err
+  }
+
+  t.equals(err['code'], 'EEXIST', 'dest folder not ignored')
+  t.end()
+})
+
 test('rename target file if it exists', async (t) => {
   const temp = tempy.directory()
   t.comment(`testing in ${temp}`)
@@ -86,3 +105,19 @@ test('concurrently creating the same symlink twice', async (t) => {
 
   t.end()
 })
+
+test('reusing the existing symlink if it already points to the needed location', async (t) => {
+  const temp = tempy.directory()
+  t.comment(`testing in ${temp}`)
+  process.chdir(temp)
+
+  await writeJsonFile('src/file.json', { ok: true })
+
+  await symlink('src', 'dest/subdir')
+  const { reused } = await symlink('src', 'dest/subdir')
+
+  t.equal(reused, true)
+  t.deepEqual(await import(path.resolve('dest/subdir/file.json')), { ok: true })
+
+  t.end()
+})