Merge pull request #12105 from meteor/feature/package-minifier-css-async

Create async method `CssTools.minifyCssAsync`

packages/minifier-css/minifier-async-tests.js

@@ -0,0 +1,51 @@
+import { CssTools } from './minifier';
+const TEST_CASES = [
+  ['a \t\n{ color: red } \n', 'a{color:red}', 'whitespace check'],
+  [
+    'a \t\n{ color: red; margin: 1; } \n',
+    'a{color:red;margin:1}',
+    'only last one loses semicolon',
+  ],
+  [
+    'a \t\n{ color: red;;; margin: 1;;; } \n',
+    'a{color:red;margin:1}',
+    'more semicolons than needed',
+  ],
+  ['a , p \t\n{ color: red; } \n', 'a,p{color:red}', 'multiple selectors'],
+  ['body {}', '', 'removing empty rules'],
+  [
+    '*.my-class { color: #fff; }',
+    '.my-class{color:#fff}',
+    'removing universal selector',
+  ],
+  [
+    'p > *.my-class { color: #fff; }',
+    'p>.my-class{color:#fff}',
+    'removing optional whitespace around ">" in selector',
+  ],
+  [
+    'p +  *.my-class { color: #fff; }',
+    'p+.my-class{color:#fff}',
+    'removing optional whitespace around "+" in selector',
+  ],
+  [
+    'a {\n\
+  font:12px \'Helvetica\',"Arial",\'Nautica\';\n\
+  background:url("/some/nice/picture.png");\n}',
+    'a{font:12px Helvetica,Arial,Nautica;background:url(/some/nice/picture.png)}',
+    'removing quotes in font and url (if possible)',
+  ],
+  ['/* no comments */ a { color: red; }', 'a{color:red}', 'remove comments'],
+];
+
+Tinytest.addAsync(
+  '[Async] minifier-css - simple CSS minification',
+  async (test) => {
+    const promises = TEST_CASES.map(([css, expected, desc]) =>
+      CssTools.minifyCssAsync(css).then((minifiedCss) => {
+        test.equal(minifiedCss[0], expected, desc);
+      })
+    );
+    return Promise.all(promises);
+  }
+);

packages/minifier-css/minifier.js

@@ -1,6 +1,5 @@
 import path from 'path';
 import url from 'url';
-import Future from 'fibers/future';
 import postcss from 'postcss';
 import cssnano from 'cssnano';
 
@@ -65,23 +64,21 @@ const CssTools = {
    * @return {String[]} Array containing the minified CSS.
    */
   minifyCss(cssText) {
-    const f = new Future;
-    postcss([
-      cssnano({ safe: true }),
-    ]).process(cssText, {
-      from: void 0,
-    }).then(result => {
-      f.return(result.css);
-    }).catch(error => {
-      f.throw(error);
-    });
-    const minifiedCss = f.wait();
+    return Promise.await(CssTools.minifyCssAsync(cssText));
+  },
 
-    // Since this function has always returned an array, we'll wrap the
-    // minified css string in an array before returning, even though we're
-    // only ever returning one minified css string in that array (maintaining
-    // backwards compatibility).
-    return [minifiedCss];
+  /**
+   * Minify the passed in CSS string.
+   *
+   * @param {string} cssText CSS string to minify.
+   * @return {Promise<String[]>} Array containing the minified CSS.
+   */
+  async minifyCssAsync(cssText) {
+    return await postcss([cssnano({ safe: true })])
+      .process(cssText, {
+        from: void 0,
+      })
+      .then((result) => [result.css]);
   },
 
   /**
@@ -187,6 +184,7 @@ if (typeof Profile !== 'undefined') {
     'parseCss',
     'stringifyCss',
     'minifyCss',
+    'minifyCssAsync',
     'mergeCssAsts',
     'rewriteCssUrls',
   ].forEach(funcName => {

packages/minifier-css/package.js

@@ -19,6 +19,7 @@ Package.onTest(function (api) {
   api.use('tinytest');
   api.addFiles([
     'minifier-tests.js',
+    'minifier-async-tests.js',
     'urlrewriting-tests.js'
   ], 'server');
 });

packages/standard-minifier-css/plugin/minify-css.js

@@ -60,7 +60,7 @@ class CssToolsMinifier {
         path: 'merged-stylesheets.css'
       }];
     } else {
-      const minifiedFiles = CssTools.minifyCss(merged.code);
+      const minifiedFiles = await CssTools.minifyCssAsync(merged.code);
 
       result = minifiedFiles.map(minified => ({
         data: minified