New: Add Promise support when no callback specified (closes #5)

.eslintrc

@@ -1,3 +1,6 @@
 {
-  "extends": "gulp"
+  "extends": "gulp",
+  "globals": {
+    "Promise": true
+  }
 }

.travis.yml

@@ -5,7 +5,5 @@ node_js:
   - '8'
   - '6'
   - '4'
-  - '0.12'
-  - '0.10'
 after_script:
   - npm run coveralls

README.md

@@ -15,6 +15,7 @@ Check if a directory is empty.
 ```js
 var emptyDir = require('empty-dir');
 
+// Using an error-back
 emptyDir('./', function (err, result) {
   if (err) {
     console.error(err);
@@ -23,6 +24,11 @@ emptyDir('./', function (err, result) {
   }
 });
 
+// Using a Promise
+emptyDir('./').then(function (result) {
+  console.log('Directory is empty:', result);
+})
+
 var result = emptyDir.sync('./test/empty');
 console.log('Directory is empty:', result);
 ```

appveyor.yml

@@ -4,8 +4,6 @@
 environment:
   matrix:
     # node.js
-    - nodejs_version: "0.10"
-    - nodejs_version: "0.12"
     - nodejs_version: "4"
     - nodejs_version: "6"
     - nodejs_version: "8"

index.js

@@ -8,30 +8,44 @@ function emptyDir(dir, filter, cb) {
     filter = null;
   }
 
-  if (typeof cb !== 'function') {
+  if (cb && typeof cb !== 'function') {
     throw new TypeError('expected callback to be a function');
   }
 
-  if (Array.isArray(dir)) {
-    cb(null, isEmpty(dir, filter));
-    return;
-  }
-
-  if (typeof dir !== 'string') {
-    cb(new TypeError('expected a directory or array of files'));
-    return;
+  if (!Array.isArray(dir) && typeof dir !== 'string') {
+    throw new TypeError('expected a directory or array of files');
   }
 
-  fs.stat(dir, function(err, stat) {
-    if (err || !stat.isDirectory()) {
-      cb(null, false);
-      return;
+  var p = new Promise(function(resolve, reject) {
+    if (Array.isArray(dir)) {
+      return resolve(isEmpty(dir, filter));
     }
 
-    fs.readdir(dir, function(err, files) {
-      cb(err, isEmpty(files, filter));
+    fs.stat(dir, function(err, stat) {
+      if (err || !stat.isDirectory()) {
+        return resolve(false);
+      }
+
+      fs.readdir(dir, function(err, files) {
+        if (err) {
+          return reject(err);
+        }
+
+        resolve(isEmpty(files, filter));
+      });
     });
   });
+
+  if (cb) {
+    p.then(function(result) {
+      cb(null, result);
+    }).catch(function(err) {
+      cb(err);
+    });
+    return;
+  }
+
+  return p;
 }
 
 /**

package.json

@@ -11,7 +11,7 @@
   "repository": "gulpjs/empty-dir",
   "license": "MIT",
   "engines": {
-    "node": ">= 0.10"
+    "node": ">= 4"
   },
   "main": "index.js",
   "files": [

test/index.js

@@ -15,9 +15,9 @@ function isGarbageFile(filename) {
 }
 
 describe('emptyDir', function() {
-  it('should throw when a callback is not passed', function(done) {
+  it('should throw when the callback is not a function', function(done) {
     expect(function() {
-      emptyDir('./');
+      emptyDir('./', 'foo', 'bar');
     }).toThrow(/expected/);
     done();
   });
@@ -27,11 +27,10 @@ describe('emptyDir', function() {
       emptyDir.sync(null);
     }).toThrow();
 
-    emptyDir(null, function(err) {
-      expect(err).toExist();
-      expect(/expected/.test(err.message)).toEqual(true);
-      done();
-    });
+    expect(function() {
+      emptyDir(null);
+    }).toThrow();
+    done();
   });
 
   it('should take an array', function(done) {
@@ -64,8 +63,7 @@ describe('emptyDir', function() {
   it('should be false if a directory does not exist', function(done) {
     expect(emptyDir.sync('./foo/bar/baz')).toEqual(false);
     emptyDir('./foo/bar/baz', function(err, empty) {
-      expect(empty).toEqual(false);
-      done();
+      done(err);
     });
   });
 
@@ -76,4 +74,35 @@ describe('emptyDir', function() {
       done();
     });
   });
+
+  describe('without a callback argument', function() {
+    it('should return a Promise', function(done) {
+      var p = emptyDir('./test/empty');
+      expect(p.then).toBeA('function');
+      p.then(function() {
+        done();
+      });
+    });
+
+    it('should resolve with false if a directory does not exist', function(done) {
+      emptyDir('/root/super/secret').then(function(result) {
+        expect(result).toEqual(false);
+        done();
+      });
+    });
+
+    it('should resolve with true if a directory is empty', function(done) {
+      emptyDir('./test/empty').then(function(result) {
+        expect(result).toEqual(true);
+        done();
+      });
+    });
+
+    it('should resolve with false if a directory is not empty', function(done) {
+      emptyDir('./test').then(function(result) {
+        expect(result).toEqual(false);
+        done();
+      });
+    });
+  });
 });