Use static-module to extract css

Author: ajoslin

index.js

@@ -1,7 +1,6 @@
 const ConcatStream = require('concat-stream')
-const isRequire = require('is-require')()
+const staticModule = require('static-module')
 const through = require('through2')
-const falafel = require('falafel')
 const assert = require('assert')
 const fs = require('fs')
 
@@ -22,16 +21,26 @@ function cssExtract (bundle, opts) {
   addHooks()
 
   function addHooks () {
-    // run before the "debug" step in browserify pipeline
-    bundle.pipeline.get('debug').unshift(through.obj(write, flush))
     const writeStream = (typeof outFile === 'function')
       ? outFile()
-      : ConcatStream(writeOutFile)
+      : ConcatStream(fs.writeFileSync.bind(fs, outFile))
+
+    // run before the "debug" step in browserify pipeline
+    bundle.pipeline.get('debug').unshift(through.obj(write, flush))
 
     function write (chunk, enc, cb) {
-      const css = extract(chunk)
-      writeStream.write(css)
-      cb(null, chunk)
+      // A small performance boost: don't do ast parsing unless we know it's needed
+      if (String(chunk.source).indexOf('insert-css') === -1) {
+        return cb(null, chunk)
+      }
+
+      var sm = createStaticModule(writeStream)
+      sm.write(chunk.source)
+      sm.pipe(ConcatStream(function (source) {
+        chunk.source = source
+        cb(null, chunk)
+      }))
+      sm.end()
     }
 
     // close stream and signal end
@@ -40,29 +49,10 @@ function cssExtract (bundle, opts) {
       cb()
     }
   }
-
-  function writeOutFile (buffer) {
-    fs.writeFileSync(outFile, buffer)
-  }
 }
 
-// extract css from chunks
-// obj -> str
-function extract (chunk) {
-  // Do a performant check before building the ast
-  if (String(chunk.source).indexOf('insert-css') === -1) return ''
-
-  const css = []
-  const ast = falafel(chunk.source, { ecmaVersion: 6 }, walk)
-  chunk.source = ast.toString()
-  return css.join('\n')
-
-  function walk (node) {
-    if (!isRequire(node)) return
-    if (!node.arguments) return
-    if (!node.arguments[0]) return
-    if (node.arguments[0].value !== 'insert-css') return
-    css.push(node.parent.arguments[0].value)
-    node.parent.update('0')
-  }
+function createStaticModule (writeStream) {
+  return staticModule({
+    'insert-css': writeStream.write.bind(writeStream)
+  })
 }

package.json

@@ -21,8 +21,7 @@
   "license": "MIT",
   "dependencies": {
     "concat-stream": "^1.5.1",
-    "falafel": "^1.2.0",
-    "is-require": "0.0.1",
+    "static-module": "^1.3.0",
     "through2": "^2.0.1"
   },
   "devDependencies": {

test/expected-static.css

@@ -0,0 +1 @@
+.foo {background: green}

test/index.js

@@ -14,7 +14,7 @@ test('css-extract', function (t) {
     t.throws(cssExtract.bind(null, {}), 123, /object/)
   })
 
-  t.test('should extract css', function (t) {
+  t.test('should extract sheetify css to given stream', function (t) {
     t.plan(2)
     browserify(path.join(__dirname, 'source.js'))
       .transform('sheetify/transform')
@@ -31,7 +31,7 @@ test('css-extract', function (t) {
     }
   })
 
-  t.test('should write file', function (t) {
+  t.test('should extract sheetify css to file', function (t) {
     t.plan(3)
     tmpDir({unsafeCleanup: true}, onDir)
 
@@ -54,4 +54,42 @@ test('css-extract', function (t) {
         })
     }
   })
+
+  t.test('should extract static insert-css statements', function (t) {
+    t.plan(2)
+    browserify(path.join(__dirname, 'source-static.js'))
+      .plugin(cssExtract, { out: createWs })
+      .bundle()
+
+    function createWs () {
+      return bl(function (err, data) {
+        t.ifError(err, 'no error')
+        const exPath = path.join(__dirname, './expected-static.css')
+        const expected = fs.readFileSync(exPath, 'utf8').trim()
+        t.equal(String(data), expected, 'extracted all the CSS')
+      })
+    }
+  })
+
+  t.test('should not extract dynamic insert-css statements', function (t) {
+    t.plan(4)
+    const sourcePath = path.join(__dirname, 'source-dynamic.js')
+
+    browserify(sourcePath)
+      .plugin(cssExtract, { out: readCss })
+      .bundle(readJs)
+
+    function readCss () {
+      return bl(function (err, data) {
+        t.ifError(err, 'no error')
+        t.equal(String(data), '', 'no css extracted')
+      })
+    }
+
+    function readJs (err, data) {
+      t.ifError(err, 'no error')
+      const source = fs.readFileSync(sourcePath, 'utf8')
+      t.ok(String(data).indexOf(String(source)) !== -1, 'source is still in built bundle')
+    }
+  })
 })

test/source-dynamic.js

@@ -0,0 +1,5 @@
+insert('.foo {}')
+
+function insert (foo) {
+  require('insert-css')(foo)
+}

test/source-static.js

@@ -0,0 +1,3 @@
+var insertCss = require('insert-css')
+
+insertCss('.foo {background: green}')