add support for promises; closes douzi8#6

base64-img.js

@@ -5,7 +5,7 @@ var request = require('ajax-request');
 function base64(filename, data) {
   var extname = path.extname(filename).substr(1);
   extname = extname || 'png';
-  
+
   return 'data:image/' + extname + ';base64,' + data.toString('base64');
 }
 
@@ -28,16 +28,56 @@ function img(data) {
   };
 }
 
+function base64Promise(filename) {
+  return new Promise((resolve, reject) => {
+    fs.readFile(filename, function (err, data) {
+      if (err) reject(err);
+
+      resolve(base64(filename, data));
+    });
+  });
+};
+
+function requestBase64Promise(url) {
+  return new Promise((resolve, reject) => {
+    request({
+      url: url,
+      isBuffer: true
+    }, function (err, res, body) {
+      if (err) return reject(err);
+
+      var data = 'data:' + res.headers['content-type'] + ';base64,' + body.toString('base64');
+      resolve({ res, data });
+    });
+  });
+};
+
+function imgPromise(data, destpath, name) {
+  return new Promise((resolve, reject) => {
+    var result = img(data);
+    var filepath = path.join(destpath, name + result.extname);
+
+    fs.writeFile(filepath, result.base64, { encoding: 'base64' }, function (err) {
+      if (err) return reject(err);
+      resolve(filepath);
+    });
+  });
+};
+
 /**
  * @description
  * Get image file base64 data
  * @example
  * base64Img.base64('path/demo.png', function(err, data) {})
+ * @example
+ * base64Img.base64('path/demo.png').then(function(data) {
+ * 
+ * });
  */
-exports.base64 = function(filename, callback) {
-  if (!callback) callback = util.noop;
+exports.base64 = function (filename, callback) {
+  if (!callback) return base64Promise(filename);
 
-  fs.readFile(filename, function(err, data) {
+  fs.readFile(filename, function (err, data) {
     if (err) return callback(err);
 
     callback(null, base64(filename, data));
@@ -50,7 +90,7 @@ exports.base64 = function(filename, callback) {
  * @example
  * var data = base64Img.base64Sync('path/demo.png');
  */
-exports.base64Sync = function(filename) {
+exports.base64Sync = function (filename) {
   var data = fs.readFileSync(filename);
 
   return base64(filename, data);
@@ -66,8 +106,16 @@ exports.base64Sync = function(filename) {
  * 
  *   }
  * );
+ * @example
+ * request.base64(
+ *   'http://webresource.c-ctrip.com/ResCRMOnline/R5/html5/images/57.png',
+ * ).then(function({res, data}) {
+ * 
+ * });
  */
-exports.requestBase64 = function(url, callback) {
+exports.requestBase64 = function (url, callback) {
+  if (!callback) return requestBase64Promise(url);
+
   request({
     url: url,
     isBuffer: true
@@ -84,12 +132,16 @@ exports.requestBase64 = function(url, callback) {
  * Convert image base64 data to img
  * @example
  * base64Img.img('data:image/png;base64,...', 'dest', '1', function(err, filepath) {});
+ * @example
+ * base64Img.img('data:image/png;base64,...', 'dest', '1').then(function(filepath) {});
  */
-exports.img = function(data, destpath, name, callback) {
+exports.img = function (data, destpath, name, callback) {
+  if (!callback) return imgPromise(data, destpath, name);
+
   var result = img(data);
   var filepath = path.join(destpath, name + result.extname);
 
-  fs.writeFile(filepath, result.base64, { encoding: 'base64' }, function(err) {
+  fs.writeFile(filepath, result.base64, { encoding: 'base64' }, function (err) {
     callback(err, filepath);
   });
 };
@@ -100,7 +152,7 @@ exports.img = function(data, destpath, name, callback) {
  * @example
  * var filepath = base64Img.imgSync('data:image/png;base64,...', 'dest', '1');
  */
-exports.imgSync = function(data, destpath, name) {
+exports.imgSync = function (data, destpath, name) {
   var result = img(data);
   var filepath = path.join(destpath, name + result.extname);