Initial dead code elimination

package.json

@@ -7,10 +7,12 @@
     "test": "test"
   },
   "dependencies": {
+    "lodash.partialright": "^3.1.1",
     "postcss": "^4.1.11",
     "postcss-modules-extract-imports": "^0.0.5",
     "postcss-modules-local-by-default": "^0.0.9",
-    "postcss-modules-scope": "^0.0.8"
+    "postcss-modules-scope": "^0.0.8",
+    "selector-has": "^1.0.0"
   },
   "devDependencies": {
     "babel": "^5.5.4",

src/file-system-loader.js

@@ -1,6 +1,9 @@
 import Core from './index.js'
 import fs from 'fs'
 import path from 'path'
+import {parse} from 'postcss';
+import selectorHas from 'selector-has'
+import partialRight from 'lodash.partialright'
 
 // Sorts dependencies in the following way:
 // AAA comes before AA and A
@@ -28,7 +31,7 @@ export default class FileSystemLoader {
     this.tokensByFile = {};
   }
 
-  fetch( _newPath, relativeTo, _trace ) {
+  fetch( _newPath, relativeTo, _trace, composedClasses ) {
     let newPath = _newPath.replace( /^["']|["']$/g, "" ),
       trace = _trace || String.fromCharCode( this.importNr++ )
     return new Promise( ( resolve, reject ) => {
@@ -44,12 +47,36 @@ export default class FileSystemLoader {
         catch (e) {}
       }
 
-      const tokens = this.tokensByFile[fileRelativePath]
-      if (tokens) { return resolve(tokens) }
+      fs.readFile( fileRelativePath, 'utf-8', ( err, source ) => {
+
+      if (composedClasses) {
+        let root = parse(source);
+
+        let exportedNames = {};
+
+        root.each( node => {
+          if ( node.type === 'rule' && node.selector === ':export' ) {
+            node.each( decl => {
+              exportedNames[decl.prop] = decl.value;
+            } )
+          }
+        } )
+
+        root.each(decl => {
+          if (!composedClasses.some(name => {
+            if (exportedNames[name]) {
+              name = exportedNames[name]
+            }
+            return decl.selector === ':export' || selectorHas(decl.selector, name)
+          })) {
+            decl.removeSelf()
+          }
+        })
+        source = root.toString()
+      }
 
-      fs.readFile( fileRelativePath, "utf-8", ( err, source ) => {
         if ( err ) reject( err )
-        this.core.load( source, rootRelativePath, trace, this.fetch.bind( this ) )
+        this.core.load( source, rootRelativePath, trace, partialRight(this.fetch.bind( this ), composedClasses) )
           .then( ( { injectableSource, exportTokens } ) => {
             this.sources[trace] = injectableSource
             this.tokensByFile[fileRelativePath] = exportTokens

src/parser.js

@@ -16,10 +16,12 @@ export default class Parser {
   }
 
   fetchAllImports( css ) {
+    let importedClasses = []
     let imports = []
     css.each( node => {
       if ( node.type == "rule" && node.selector.match( importRegexp ) ) {
-        imports.push( this.fetchImport( node, css.source.input.from, imports.length ) )
+        importedClasses = node.nodes.map(decl => decl.value);
+        imports.push( this.fetchImport( node, css.source.input.from, imports.length, importedClasses ) )
       }
     } )
     return imports
@@ -51,10 +53,11 @@ export default class Parser {
     exportNode.removeSelf()
   }
 
-  fetchImport( importNode, relativeTo, depNr ) {
+  fetchImport( importNode, relativeTo, depNr, importedClasses ) {
     let file = importNode.selector.match( importRegexp )[1],
       depTrace = this.trace + String.fromCharCode(depNr)
-    return this.pathFetcher( file, relativeTo, depTrace ).then( exports => {
+
+    return this.pathFetcher( file, relativeTo, depTrace, importedClasses ).then( exports => {
       importNode.each( decl => {
         if ( decl.type == 'decl' ) {
           this.translations[decl.prop] = exports[decl.value]

test/test-cases/multiple-composes/c.css

@@ -0,0 +1,14 @@
+.c1 {
+  composes: d1 from "./d.css";
+  color: #c1c1c1;
+}
+
+.c2 {
+  composes: d2 from "./d.css";
+  color: #c2c2c2;
+}
+
+.c3 {
+  composes: d3 from "./d.css";
+  color: #c3c3c3;
+}

test/test-cases/multiple-composes/d.css

@@ -0,0 +1,15 @@
+.d1 {
+  color: #d1d1d1;
+}
+
+.d2 {
+  color: #d2d2d2;
+}
+
+.d3 {
+  color: #d3d3d3;
+}
+
+.d1 .another {
+  color: #555;
+}

test/test-cases/multiple-composes/expected.css

@@ -0,0 +1,25 @@
+._multiple_composes_d__d1 {
+  color: #d1d1d1;
+}
+
+._multiple_composes_d__d2 {
+  color: #d2d2d2;
+}
+
+._multiple_composes_d__d1 ._multiple_composes_d__another {
+  color: #555;
+}
+._multiple_composes_c__c1 {
+  color: #c1c1c1;
+}
+
+._multiple_composes_c__c2 {
+  color: #c2c2c2;
+}
+._multiple_composes_source__a {
+  color: #aaa;
+}
+
+._multiple_composes_source__b {
+  color: #bbb;
+}

test/test-cases/multiple-composes/expected.json

@@ -0,0 +1,4 @@
+{
+  "a": "_multiple_composes_source__a _multiple_composes_c__c1 _multiple_composes_d__d1",
+  "b": "_multiple_composes_source__b _multiple_composes_c__c2 _multiple_composes_d__d2"
+}

test/test-cases/multiple-composes/source.css

@@ -0,0 +1,9 @@
+.a {
+  composes: c1 from "./c.css";
+  color: #aaa;
+}
+
+.b {
+  composes: c2 from "./c.css";
+  color: #bbb;
+}

test/test-cases/multiple-sources/b.css

@@ -2,3 +2,11 @@
   composes: d from "./d.css";
   color: #bbb;
 }
+
+.b2 {
+  color: #b2b2b2;
+}
+
+.ab {
+  color: #ababab;
+}

test/test-cases/multiple-sources/expected.css

@@ -10,6 +10,9 @@
 ._multiple_sources_source1__a {
   color: #aaa;
 }
+._multiple_sources_b__b2 {
+  color: #b2b2b2;
+}
 ._multiple_sources_source2__foo {
   color: #f00;
 }

test/test-cases/multiple-sources/expected.json

@@ -1,4 +1,4 @@
 {
   "a": "_multiple_sources_source1__a _multiple_sources_b__b _multiple_sources_d__d _multiple_sources_c__c",
-  "foo": "_multiple_sources_source2__foo _multiple_sources_b__b _multiple_sources_d__d"
+  "foo": "_multiple_sources_source2__foo _multiple_sources_b__b2"
 }

test/test-cases/multiple-sources/source2.css

@@ -1,4 +1,4 @@
 .foo {
-  composes: b from "./b.css";
+  composes: b2 from "./b.css";
   color: #f00;
 }