Allow toBuffer to resolve Promise with info+data #143

docs/api-output.md

@@ -40,15 +40,17 @@ Write output to a Buffer.
 JPEG, PNG, WebP, and RAW output are supported.
 By default, the format will match the input image, except GIF and SVG input which become PNG output.
 
-`callback`, if present, gets three arguments `(err, buffer, info)` where:
+`callback`, if present, gets three arguments `(err, data, info)` where:
 
--   `err` is an error message, if any.
--   `buffer` is the output image data.
+-   `err` is an error, if any.
+-   `data` is the output image data.
 -   `info` contains the output image `format`, `size` (bytes), `width`, `height` and `channels`.
-    A Promises/A+ promise is returned when `callback` is not provided.
+    A Promise is returned when `callback` is not provided.
 
 **Parameters**
 
+-   `options` **[Object](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object)?** 
+    -   `options.resolveWithObject` **[Boolean](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Boolean)?** Resolve the Promise with an Object containing `data` and `info` properties instead of resolving only with `data`.
 -   `callback` **[Function](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/function)?** 
 
 Returns **[Promise](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise)<[Buffer](https://nodejs.org/api/buffer.html)>** when no callback is provided

docs/changelog.md

@@ -4,6 +4,12 @@
 
 Requires libvips v8.4.2.
 
+#### v0.17.3 - TBD
+
+* Allow toBuffer to optionally resolve a Promise with both info and data.
+  [#143](https://github.com/lovell/sharp/issues/143)
+  [@salzhrani](https://github.com/salzhrani)
+
 #### v0.17.2 - 11<sup>th</sup> February 2017
 
 * Ensure Readable side of Stream can start flowing after Writable side has finished.

lib/constructor.js

@@ -134,6 +134,7 @@ const Sharp = function (input, options) {
     streamOut: false,
     withMetadata: false,
     withMetadataOrientation: -1,
+    resolveWithObject: false,
     // output format
     jpegQuality: 80,
     jpegProgressive: false,

lib/output.js

@@ -48,17 +48,24 @@ const toFile = function toFile (fileOut, callback) {
  * JPEG, PNG, WebP, and RAW output are supported.
  * By default, the format will match the input image, except GIF and SVG input which become PNG output.
  *
- * `callback`, if present, gets three arguments `(err, buffer, info)` where:
- * - `err` is an error message, if any.
- * - `buffer` is the output image data.
+ * `callback`, if present, gets three arguments `(err, data, info)` where:
+ * - `err` is an error, if any.
+ * - `data` is the output image data.
  * - `info` contains the output image `format`, `size` (bytes), `width`, `height` and `channels`.
- * A Promises/A+ promise is returned when `callback` is not provided.
+ * A Promise is returned when `callback` is not provided.
  *
+ * @param {Object} [options]
+ * @param {Boolean} [options.resolveWithObject] Resolve the Promise with an Object containing `data` and `info` properties instead of resolving only with `data`.
  * @param {Function} [callback]
  * @returns {Promise<Buffer>} - when no callback is provided
  */
-const toBuffer = function toBuffer (callback) {
-  return this._pipeline(callback);
+const toBuffer = function toBuffer (options, callback) {
+  if (is.object(options)) {
+    if (is.bool(options.resolveWithObject)) {
+      this.options.resolveWithObject = options.resolveWithObject;
+    }
+  }
+  return this._pipeline(is.fn(options) ? options : callback);
 };
 
 /**
@@ -423,24 +430,32 @@ const _pipeline = function _pipeline (callback) {
       return new Promise(function (resolve, reject) {
         that.on('finish', function () {
           that._flattenBufferIn();
-          sharp.pipeline(that.options, function (err, data) {
+          sharp.pipeline(that.options, function (err, data, info) {
             if (err) {
               reject(err);
+            } else {
+              if (that.options.resolveWithObject) {
+                resolve({ data: data, info: info });
               } else {
                 resolve(data);
               }
+            }
           });
         });
       });
     } else {
       // output=promise, input=file/buffer
       return new Promise(function (resolve, reject) {
-        sharp.pipeline(that.options, function (err, data) {
+        sharp.pipeline(that.options, function (err, data, info) {
           if (err) {
             reject(err);
+          } else {
+            if (that.options.resolveWithObject) {
+              resolve({ data: data, info: info });
             } else {
               resolve(data);
             }
+          }
         });
       });
     }

test/unit/io.js

@@ -77,16 +77,58 @@ describe('Input/output', function () {
     readable.pipe(pipeline);
   });
 
-  it('Read from Stream and write to Buffer via Promise', function (done) {
-    const readable = fs.createReadStream(fixtures.inputJpg);
+  it('Read from Stream and write to Buffer via Promise resolved with Buffer', function () {
     const pipeline = sharp().resize(1, 1);
-    pipeline.toBuffer().then(function (data) {
+    fs.createReadStream(fixtures.inputJpg).pipe(pipeline);
+    return pipeline
+      .toBuffer({resolveWithObject: false})
+      .then(function (data) {
+        assert.strictEqual(true, data instanceof Buffer);
         assert.strictEqual(true, data.length > 0);
-      done();
-    }).catch(function (err) {
-      throw err;
       });
-    readable.pipe(pipeline);
+  });
+
+  it('Read from Stream and write to Buffer via Promise resolved with Object', function () {
+    const pipeline = sharp().resize(1, 1);
+    fs.createReadStream(fixtures.inputJpg).pipe(pipeline);
+    return pipeline
+      .toBuffer({resolveWithObject: true})
+      .then(function (object) {
+        assert.strictEqual('object', typeof object);
+        assert.strictEqual('object', typeof object.info);
+        assert.strictEqual('jpeg', object.info.format);
+        assert.strictEqual(1, object.info.width);
+        assert.strictEqual(1, object.info.height);
+        assert.strictEqual(3, object.info.channels);
+        assert.strictEqual(true, object.data instanceof Buffer);
+        assert.strictEqual(true, object.data.length > 0);
+      });
+  });
+
+  it('Read from File and write to Buffer via Promise resolved with Buffer', function () {
+    return sharp(fixtures.inputJpg)
+      .resize(1, 1)
+      .toBuffer({resolveWithObject: false})
+      .then(function (data) {
+        assert.strictEqual(true, data instanceof Buffer);
+        assert.strictEqual(true, data.length > 0);
+      });
+  });
+
+  it('Read from File and write to Buffer via Promise resolved with Object', function () {
+    return sharp(fixtures.inputJpg)
+      .resize(1, 1)
+      .toBuffer({resolveWithObject: true})
+      .then(function (object) {
+        assert.strictEqual('object', typeof object);
+        assert.strictEqual('object', typeof object.info);
+        assert.strictEqual('jpeg', object.info.format);
+        assert.strictEqual(1, object.info.width);
+        assert.strictEqual(1, object.info.height);
+        assert.strictEqual(3, object.info.channels);
+        assert.strictEqual(true, object.data instanceof Buffer);
+        assert.strictEqual(true, object.data.length > 0);
+      });
   });
 
   it('Read from Stream and write to Stream', function (done) {