Update fs promise shims to support latest Node functions (#747)

* Add promise support for fs.writev() * Add promise support for fs.opendir() Sort array to match Node docs * Fix tests for fs.writev() * Fix requested changes
jprichardson · Feb 3, 2020 · 2e4fcae · 2e4fcae
1 parent a6c1547
commit 2e4fcae
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diff --git a/README.md b/README.md
@@ -143,7 +143,7 @@ Methods
 - [writeJsonSync](docs/writeJson-sync.md)
 
 
-**NOTE:** You can still use the native Node.js methods. They are promisified and copied over to `fs-extra`. See [notes on `fs.read()` & `fs.write()`](docs/fs-read-write.md)
+**NOTE:** You can still use the native Node.js methods. They are promisified and copied over to `fs-extra`. See [notes on `fs.read()`, `fs.write()`, & `fs.writev()`](docs/fs-read-write-writev.md)
 
 ### What happened to `walk()` and `walkSync()`?
 

diff --git a/docs/fs-read-write.md → docs/fs-read-write-writev.md b/docs/fs-read-write.md → docs/fs-read-write-writev.md
@@ -1,6 +1,6 @@
 # About `fs.read()` & `fs.write()`
 
-[`fs.read()`](https://nodejs.org/api/fs.html#fs_fs_read_fd_buffer_offset_length_position_callback) & [`fs.write()`](https://nodejs.org/api/fs.html#fs_fs_write_fd_buffer_offset_length_position_callback) are different from other `fs` methods in that their callbacks are called with 3 arguments instead of the usual 2 arguments.
+[`fs.read()`](https://nodejs.org/api/fs.html#fs_fs_read_fd_buffer_offset_length_position_callback), [`fs.write()`](https://nodejs.org/api/fs.html#fs_fs_write_fd_buffer_offset_length_position_callback), & [`fs.writev()`](https://nodejs.org/api/fs.html#fs_fs_writev_fd_buffers_position_callback) are different from other `fs` methods in that their callbacks are called with 3 arguments instead of the usual 2 arguments.
 
 If you're using them with callbacks, they will behave as usual. However, their promise usage is a little different. `fs-extra` promisifies these methods like [`util.promisify()`](https://nodejs.org/api/util.html#util_util_promisify_original) (only available in Node 8+) does.
 
@@ -37,3 +37,12 @@ async function example () {
   const { bytesWritten, buffer } = await fs.write(fd, Buffer.alloc(length), offset, length, position)
 }
 ```
+
+## `fs.writev()`
+
+```js
+// With async/await:
+async function example () {
+  const { bytesWritten, buffers } = await fs.writev(fd, buffers, position)
+}
+```
diff --git a/lib/fs/__tests__/multi-param.test.js b/lib/fs/__tests__/multi-param.test.js
@@ -11,6 +11,8 @@ const SIZE = 1000
 
 // Used for tests on Node 7.2.0+ only
 const onNode7it = semver.gte(process.version, '7.2.0') ? it : it.skip
+// Used for tests on Node 12.9.0+ only
+const describeNode12 = semver.gte(process.version, '12.9.0') ? describe : describe.skip
 
 describe('fs.read()', () => {
   let TEST_FILE
@@ -152,3 +154,59 @@ describe('fs.write()', () => {
     })
   })
 })
+
+describeNode12('fs.writev()', () => {
+  let TEST_FILE
+  let TEST_DATA
+  let TEST_FD
+
+  beforeEach(() => {
+    TEST_FILE = path.join(os.tmpdir(), 'fs-extra', 'writev-test-file')
+    TEST_DATA = [crypto.randomBytes(SIZE / 2), crypto.randomBytes(SIZE / 2)]
+    fs.ensureDirSync(path.dirname(TEST_FILE))
+    TEST_FD = fs.openSync(TEST_FILE, 'w')
+  })
+
+  afterEach(() => {
+    return fs.close(TEST_FD)
+      .then(() => fs.remove(TEST_FILE))
+  })
+
+  describe('with promises', () => {
+    it('returns an object', () => {
+      return fs.writev(TEST_FD, TEST_DATA, 0)
+        .then(({ bytesWritten, buffers }) => {
+          assert.strictEqual(bytesWritten, SIZE, 'bytesWritten is correct')
+          assert.deepStrictEqual(buffers, TEST_DATA, 'data is correct')
+        })
+    })
+
+    it('returns an object when minimal arguments are passed', () => {
+      return fs.writev(TEST_FD, TEST_DATA)
+        .then(({ bytesWritten, buffers }) => {
+          assert.strictEqual(bytesWritten, SIZE, 'bytesWritten is correct')
+          assert.deepStrictEqual(buffers, TEST_DATA, 'data is correct')
+        })
+    })
+  })
+
+  describe('with callbacks', () => {
+    it('works', done => {
+      fs.writev(TEST_FD, TEST_DATA, 0, (err, bytesWritten, buffers) => {
+        assert.ifError(err)
+        assert.strictEqual(bytesWritten, SIZE, 'bytesWritten is correct')
+        assert.deepStrictEqual(buffers, TEST_DATA, 'data is correct')
+        done()
+      })
+    })
+
+    it('works when minimal arguments are passed', done => {
+      fs.writev(TEST_FD, TEST_DATA, (err, bytesWritten, buffers) => {
+        assert.ifError(err)
+        assert.strictEqual(bytesWritten, SIZE, 'bytesWritten is correct')
+        assert.deepStrictEqual(buffers, TEST_DATA, 'data is correct')
+        done()
+      })
+    })
+  })
+})
diff --git a/lib/fs/index.js b/lib/fs/index.js
@@ -18,15 +18,16 @@ const api = [
   'fsync',
   'ftruncate',
   'futimes',
-  'lchown',
   'lchmod',
+  'lchown',
   'link',
   'lstat',
   'mkdir',
   'mkdtemp',
   'open',
-  'readFile',
+  'opendir',
   'readdir',
+  'readFile',
   'readlink',
   'realpath',
   'rename',
@@ -39,6 +40,7 @@ const api = [
   'writeFile'
 ].filter(key => {
   // Some commands are not available on some systems. Ex:
+  // fs.opendir was added in Node.js v12.12.0
   // fs.copyFile was added in Node.js v8.5.0
   // fs.mkdtemp was added in Node.js v5.10.0
   // fs.lchown is not available on at least some Linux
@@ -71,7 +73,7 @@ exports.exists = function (filename, callback) {
   })
 }
 
-// fs.read() & fs.write need special treatment due to multiple callback args
+// fs.read(), fs.write(), & fs.writev() need special treatment due to multiple callback args
 
 exports.read = function (fd, buffer, offset, length, position, callback) {
   if (typeof callback === 'function') {
@@ -103,6 +105,25 @@ exports.write = function (fd, buffer, ...args) {
   })
 }
 
+// fs.writev only available in Node v12.9.0+
+if (typeof fs.writev === 'function') {
+  // Function signature is
+  // s.writev(fd, buffers[, position], callback)
+  // We need to handle the optional arg, so we use ...args
+  exports.writev = function (fd, buffers, ...args) {
+    if (typeof args[args.length - 1] === 'function') {
+      return fs.writev(fd, buffers, ...args)
+    }
+
+    return new Promise((resolve, reject) => {
+      fs.writev(fd, buffers, ...args, (err, bytesWritten, buffers) => {
+        if (err) return reject(err)
+        resolve({ bytesWritten, buffers })
+      })
+    })
+  }
+}
+
 // fs.realpath.native only available in Node v9.2+
 if (typeof fs.realpath.native === 'function') {
   exports.realpath.native = u(fs.realpath.native)