feat: port @npmcli/move-file (#63)

Closes #56
npm · Nov 3, 2022 · ecbb150 · ecbb150
1 parent 1268710
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diff --git a/README.md b/README.md
@@ -7,6 +7,7 @@ polyfills, and extensions, of the core `fs` module.
 - `fs.cp` polyfill for node < 16.7.0
 - `fs.withTempDir` added
 - `fs.readdirScoped` added
+- `fs.moveFile` added
 
 ## `fs.withTempDir(root, fn, options) -> Promise`
 
@@ -57,3 +58,40 @@ const readdir = require('readdir-scoped-modules')
 const entries = await readdir('node_modules')
 // entries will be something like: ['a', '@org/foo', '@org/bar']
 ```
+
+## `fs.moveFile(source, dest, options) -> Promise`
+
+A fork of [move-file](https://github.com/sindresorhus/move-file) with
+support for Common JS.
+
+### Highlights
+
+- Promise API.
+- Supports moving a file across partitions and devices.
+- Optionally prevent overwriting an existing file.
+- Creates non-existent destination directories for you.
+- Automatically recurses when source is a directory.
+
+### Parameters
+
+- `source`: File, or directory, you want to move.
+- `dest`: Where you want the file or directory moved.
+- `options`
+  - `overwrite` (`boolean`, default: `true`): Overwrite existing destination file(s).
+
+### Usage
+
+The built-in
+[`fs.rename()`](https://nodejs.org/api/fs.html#fs_fs_rename_oldpath_newpath_callback)
+is just a JavaScript wrapper for the C `rename(2)` function, which doesn't
+support moving files across partitions or devices. This module is what you
+would have expected `fs.rename()` to be.
+
+```js
+const { moveFile } = require('@npmcli/fs');
+
+(async () => {
+	await moveFile('source/unicorn.png', 'destination/unicorn.png');
+	console.log('The file has been moved');
+})();
+```
diff --git a/lib/index.js b/lib/index.js
@@ -3,9 +3,11 @@
 const cp = require('./cp/index.js')
 const withTempDir = require('./with-temp-dir.js')
 const readdirScoped = require('./readdir-scoped.js')
+const moveFile = require('./move-file.js')
 
 module.exports = {
   cp,
   withTempDir,
   readdirScoped,
+  moveFile,
 }
diff --git a/lib/move-file.js b/lib/move-file.js
@@ -0,0 +1,78 @@
+const { dirname, join, resolve, relative, isAbsolute } = require('path')
+const fs = require('fs/promises')
+
+const pathExists = async path => {
+  try {
+    await fs.access(path)
+    return true
+  } catch (er) {
+    return er.code !== 'ENOENT'
+  }
+}
+
+const moveFile = async (source, destination, options = {}, root = true, symlinks = []) => {
+  if (!source || !destination) {
+    throw new TypeError('`source` and `destination` file required')
+  }
+
+  options = {
+    overwrite: true,
+    ...options,
+  }
+
+  if (!options.overwrite && await pathExists(destination)) {
+    throw new Error(`The destination file exists: ${destination}`)
+  }
+
+  await fs.mkdir(dirname(destination), { recursive: true })
+
+  try {
+    await fs.rename(source, destination)
+  } catch (error) {
+    if (error.code === 'EXDEV' || error.code === 'EPERM') {
+      const sourceStat = await fs.lstat(source)
+      if (sourceStat.isDirectory()) {
+        const files = await fs.readdir(source)
+        await Promise.all(files.map((file) =>
+          moveFile(join(source, file), join(destination, file), options, false, symlinks)
+        ))
+      } else if (sourceStat.isSymbolicLink()) {
+        symlinks.push({ source, destination })
+      } else {
+        await fs.copyFile(source, destination)
+      }
+    } else {
+      throw error
+    }
+  }
+
+  if (root) {
+    await Promise.all(symlinks.map(async ({ source: symSource, destination: symDestination }) => {
+      let target = await fs.readlink(symSource)
+      // junction symlinks in windows will be absolute paths, so we need to
+      // make sure they point to the symlink destination
+      if (isAbsolute(target)) {
+        target = resolve(symDestination, relative(symSource, target))
+      }
+      // try to determine what the actual file is so we can create the correct
+      // type of symlink in windows
+      let targetStat = 'file'
+      try {
+        targetStat = await fs.stat(resolve(dirname(symSource), target))
+        if (targetStat.isDirectory()) {
+          targetStat = 'junction'
+        }
+      } catch {
+        // targetStat remains 'file'
+      }
+      await fs.symlink(
+        target,
+        symDestination,
+        targetStat
+      )
+    }))
+    await fs.rm(source, { recursive: true, force: true })
+  }
+}
+
+module.exports = moveFile