Make optimize synchronous (#1322)

Ref https://github.com/svg/svgo/issues/1015

Looks like `sax` is synchronous and we do not need to listen "end"
event. This allows to avoid all callbacks and make `optimize` method
synchronous.

examples/test.js

@@ -82,7 +82,7 @@ FS.readFile(filepath, 'utf8', function(err, data) {
         throw err;
     }
 
-    svgo.optimize(data, {path: filepath}).then(function(result) {
+    const result = svgo.optimize(data, {path: filepath});
 
     console.log(result);
 
@@ -96,6 +96,4 @@ FS.readFile(filepath, 'utf8', function(err, data) {
     //     }
     // }
 
-    });
-
 });

lib/svgo.js

@@ -21,28 +21,26 @@ var SVGO = function(config) {
     this.config = CONFIG(config);
 };
 
-SVGO.prototype.optimize = function(svgstr, info) {
+SVGO.prototype.optimize = function(svgstr, info = {}) {
-    info = info || {};
+    const config = this.config;
-    return new Promise((resolve, reject) => {
+    if (config.error) {
-        if (this.config.error) {
+        throw Error(config.error);
-            reject(this.config.error);
-            return;
     }
-
+    const maxPassCount = config.multipass ? 10 : 1;
-        var config = this.config,
+    let prevResultSize = Number.POSITIVE_INFINITY;
-            maxPassCount = config.multipass ? 10 : 1,
+    let svgjs = null;
-            counter = 0,
+    for (let i = 0; i < maxPassCount; i += 1) {
-            prevResultSize = Number.POSITIVE_INFINITY,
+        svgjs = SVG2JS(svgstr);
-            optimizeOnceCallback = (svgjs) => {
+        if (svgjs.error == null) {
+            svgjs = PLUGINS(svgjs, info, config.plugins);
+        }
+        svgjs = JS2SVG(svgjs, config.js2svg);
         if (svgjs.error) {
-                    reject(svgjs.error);
+            throw Error(svgjs.error);
-                    return;
         }
-
+        info.multipassCount = i;
-                info.multipassCount = counter;
+        if (svgjs.data.length < prevResultSize) {
-                if (++counter < maxPassCount && svgjs.data.length < prevResultSize) {
+            prevResultSize = svgjs.data.length
-                    prevResultSize = svgjs.data.length;
-                    this._optimizeOnce(svgjs.data, info, optimizeOnceCallback);
         } else {
             if (config.datauri) {
                 svgjs.data = encodeSVGDatauri(svgjs.data, config.datauri);
@@ -50,27 +48,10 @@ SVGO.prototype.optimize = function(svgstr, info) {
             if (info && info.path) {
                 svgjs.path = info.path;
             }
-                    resolve(svgjs);
+            return svgjs;
         }
-            };
-
-        this._optimizeOnce(svgstr, info, optimizeOnceCallback);
-    });
-};
-
-SVGO.prototype._optimizeOnce = function(svgstr, info, callback) {
-    var config = this.config;
-
-    SVG2JS(svgstr, function(svgjs) {
-        if (svgjs.error) {
-            callback(svgjs);
-            return;
     }
-
+    return svgjs;
-        svgjs = PLUGINS(svgjs, info, config.plugins);
-
-        callback(JS2SVG(svgjs, config.js2svg));
-    });
 };
 
 /**

lib/svgo/coa.js

@@ -382,7 +382,7 @@ function processSVGData(config, info, data, output, input) {
     var startTime = Date.now(),
         prevFileSize = Buffer.byteLength(data, 'utf8');
 
-    return svgo.optimize(data, info).then(function(result) {
+    const result = svgo.optimize(data, info);
     if (config.datauri) {
         result.data = encodeSVGDatauri(result.data, config.datauri);
     }
@@ -399,7 +399,6 @@ function processSVGData(config, info, data, output, input) {
         }
     },
     error => Promise.reject(new Error(error.code === 'ENOTDIR' ? `Error: output '${output}' is not a directory.` : error)));
-    });
 }
 
 /**

lib/svgo/svg2js.js

@@ -19,16 +19,14 @@ var config = {
  * Convert SVG (XML) string to SVG-as-JS object.
  *
  * @param {String} data input data
- * @param {Function} callback
  */
-module.exports = function(data, callback) {
+module.exports = function(data) {
 
     var sax = SAX.parser(config.strict, config),
         root = new JSAPI({ elem: '#document', content: [] }),
         current = root,
         stack = [root],
-        textContext = null,
+        textContext = null;
-        parsingError = false;
 
     function pushToContent(content) {
 
@@ -163,23 +161,12 @@ module.exports = function(data, callback) {
 
     };
 
-    sax.onend = function() {
-
-        if (!this.error) {
-            callback(root);
-        } else {
-            callback({ error: this.error.message });
-        }
-
-    };
-
     try {
-        sax.write(data);
+        sax.write(data).close();
+        return root;
     } catch (e) {
-        callback({ error: e.message });
+        return { error: e.message };
-        parsingError = true;
     }
-    if (!parsingError) sax.close();
 
     function trim(elem) {
         if (!elem.content) return elem;

package.json

@@ -27,6 +27,11 @@
       "name": "Lev Solntsev",
       "email": "lev.sun@ya.ru",
       "url": "http://github.com/GreLI"
+    },
+    {
+      "name": "Bogdan Chadkin",
+      "email": "trysound@yandex.ru",
+      "url": "http://github.com/TrySound"
     }
   ],
   "repository": {

test/plugins/_index.js

@@ -44,11 +44,10 @@ describe('plugins tests', function() {
                         js2svg  : { pretty: true }
                     });
 
-                    return svgo.optimize(orig, {path: file}).then(function(result) {
+                    const result = svgo.optimize(orig, {path: file});
                     //FIXME: results.data has a '\n' at the end while it should not
                     normalize(result.data).should.be.equal(should);
                 });
-                });
 
             });
 

test/svg2js/_index.js

@@ -30,11 +30,9 @@ describe('svg2js', function() {
                     throw err;
                 }
 
-                SVG2JS(data, function(result) {
+                root = SVG2JS(data)
-                    root = result;
                 done();
             });
-            });
 
         });
 
@@ -423,9 +421,7 @@ describe('svg2js', function() {
                 }
 
                 try {
-                    SVG2JS(data, function(result) {
+                    root = SVG2JS(data)
-                        root = result;
-                    });
                 } catch (e) {
                     error = e;
                 }
@@ -473,9 +469,7 @@ describe('svg2js', function() {
             FS.readFile(filepath, 'utf8', function(err, data) {
                 if (err) throw err;
 
-                SVG2JS(data, function(result) {
+                root = SVG2JS(data);
-                    root = result;
-                });
                 done();
             });
         });

test/svgo/_index.js

@@ -30,10 +30,9 @@ describe('indentation', function() {
                 js2svg  : { pretty: true, indent: 2 }
             });
 
-            svgo.optimize(orig, {path: filepath}).then(function(result) {
+            const result = svgo.optimize(orig, {path: filepath});
             normalize(result.data).should.be.equal(should);
             done();
-            });
 
         });