New: First implementation

index.js

@@ -0,0 +1,35 @@
+'use strict';
+
+var through = require('through2');
+var normalizePath = require('normalize-path');
+
+var generate = require('./lib/generate');
+
+function identityMap() {
+
+  function transform(file, _, cb) {
+    if (!file.sourceMap || !file.isBuffer()) {
+      return cb(null, file);
+    }
+
+    var sourcePath = normalizePath(file.relative);
+    var contents = file.contents.toString();
+
+    switch (file.extname) {
+      case '.js': {
+        file.sourceMap = generate.js(sourcePath, contents);
+        break;
+      }
+      case '.css': {
+        file.sourceMap = generate.css(sourcePath, contents);
+        break;
+      }
+    }
+
+    cb(null, file);
+  }
+
+  return through.obj(transform);
+}
+
+module.exports = identityMap;

lib/generate.js

@@ -0,0 +1,65 @@
+'use strict';
+
+var css = require('css');
+var acorn = require('acorn');
+var SourceMapGenerator = require('source-map').SourceMapGenerator;
+
+function generateJs(sourcePath, fileContent) {
+  var generator = new SourceMapGenerator({ file: sourcePath });
+  var tokenizer = acorn.tokenizer(fileContent, { locations: true });
+
+  while (true) {
+    var token = tokenizer.getToken();
+
+    if (token.type.label === 'eof') {
+      break;
+    }
+    var mapping = {
+      original: token.loc.start,
+      generated: token.loc.start,
+      source: sourcePath,
+    };
+    if (token.type.label === 'name') {
+      mapping.name = token.value;
+    }
+    generator.addMapping(mapping);
+  }
+  generator.setSourceContent(sourcePath, fileContent);
+
+  return generator.toJSON();
+}
+
+function generateCss(sourcePath, fileContent) {
+  var generator = new SourceMapGenerator({ file: sourcePath });
+  var ast = css.parse(fileContent, { silent: true });
+
+  function registerTokens(ast) {
+    if (ast.position) {
+      generator.addMapping({
+        original: ast.position.start,
+        generated: ast.position.start,
+        source: sourcePath,
+      });
+    }
+
+    for (var key in ast) {
+      if (key === 'position' || !ast[key]) {
+        break;
+      }
+      if (Object.prototype.toString.call(ast[key]) === '[object Object]') {
+        registerTokens(ast[key]);
+      } else if (Array.isArray(ast[key])) {
+        ast[key].forEach(registerTokens);
+      }
+    }
+  }
+  registerTokens(ast);
+  generator.setSourceContent(sourcePath, fileContent);
+
+  return generator.toJSON();
+}
+
+module.exports = {
+  js: generateJs,
+  css: generateCss,
+};

package.json

@@ -14,16 +14,21 @@
   "main": "index.js",
   "files": [
     "LICENSE",
-    "index.js"
+    "index.js",
+    "lib"
   ],
   "scripts": {
-    "lint": "eslint . && jscs index.js test/",
+    "lint": "eslint . && jscs index.js test/index.js lib/",
     "pretest": "npm run lint",
     "test": "mocha --async-only",
     "cover": "istanbul cover _mocha --report lcovonly",
     "coveralls": "npm run cover && istanbul-coveralls"
   },
   "dependencies": {
+    "acorn": "^5.0.3",
+    "css": "^2.2.1",
+    "normalize-path": "^2.1.1",
+    "source-map": "^0.5.6",
     "through2": "^2.0.3"
   },
   "devDependencies": {

test/fixtures/helloworld.css

@@ -0,0 +1,4 @@
+body {
+	background: #eee;
+	color: #888;
+}

test/fixtures/helloworld.js

@@ -0,0 +1,5 @@
+'use strict';
+
+function helloWorld() {
+	console.log('Hello world!');
+}

test/index.js

@@ -0,0 +1,166 @@
+'use strict';
+
+var fs = require('fs');
+var path = require('path');
+
+var expect = require('expect');
+
+var miss = require('mississippi');
+var File = require('vinyl');
+
+var generate = require('../lib/generate');
+
+var identityMap = require('../');
+
+var pipe = miss.pipe;
+var from = miss.from;
+var concat = miss.concat;
+
+var jsContent = fs.readFileSync(path.join(__dirname, 'fixtures/helloworld.js'));
+var cssContent = fs.readFileSync(path.join(__dirname, 'fixtures/helloworld.css'));
+
+function makeFile() {
+  var file = new File({
+    cwd: __dirname,
+    base: __dirname + '/assets',
+    path: __dirname + '/assets/helloworld.js',
+    contents: jsContent,
+  });
+
+  file.sourceMap = {
+    version: 3,
+    file: 'helloworld.js',
+    names: [],
+    mappings: '',
+    sources: ['helloworld.js'],
+  };
+
+  return file;
+}
+
+describe('identityMap', function() {
+
+  it('ignores a file without sourceMap property', function(done) {
+    var file = makeFile();
+    delete file.sourceMap;
+
+    var spy = expect.spyOn(generate, 'js');
+
+    function assert(files) {
+      expect.restoreSpies();
+      expect(files.length).toEqual(1);
+      expect(spy).toNotHaveBeenCalled();
+    }
+
+    pipe([
+      from.obj([file]),
+      identityMap(),
+      concat(assert),
+    ], done);
+  });
+
+  it('only ignores a file without sourceMap property', function(done) {
+    var file = makeFile();
+    delete file.sourceMap;
+    var file2 = makeFile();
+
+    var spy = expect.spyOn(generate, 'js');
+
+    function assert(files) {
+      expect.restoreSpies();
+      expect(files.length).toEqual(2);
+      expect(spy.calls.length).toEqual(1);
+    }
+
+    pipe([
+      from.obj([file, file2]),
+      identityMap(),
+      concat(assert),
+    ], done);
+  });
+
+  it('ignores a non-Buffer file', function(done) {
+    var file = makeFile();
+    file.contents = null;
+
+    var spy = expect.spyOn(generate, 'js');
+
+    function assert(files) {
+      expect.restoreSpies();
+      expect(files.length).toEqual(1);
+      expect(spy).toNotHaveBeenCalled();
+    }
+
+    pipe([
+      from.obj([file]),
+      identityMap(),
+      concat(assert),
+    ], done);
+  });
+
+  it('only ignores a non-Buffer file', function(done) {
+    var file = makeFile();
+    file.contents = null;
+    var file2 = makeFile();
+
+    var spy = expect.spyOn(generate, 'js');
+
+    function assert(files) {
+      expect.restoreSpies();
+      expect(files.length).toEqual(2);
+      expect(spy.calls.length).toEqual(1);
+    }
+
+    pipe([
+      from.obj([file, file2]),
+      identityMap(),
+      concat(assert),
+    ], done);
+  });
+
+  it('adds a valid sourcemap for JS', function(done) {
+    var file = makeFile();
+
+    function assert(files) {
+      expect(files.length).toEqual(1);
+
+      var sourcemap = files[0].sourceMap;
+      expect(sourcemap).toExist();
+      expect(sourcemap.version).toEqual('3');
+      expect(sourcemap.sources[0]).toEqual('helloworld.js');
+      expect(sourcemap.sourcesContent[0]).toEqual(jsContent);
+      expect(sourcemap.names).toEqual(['helloWorld', 'console','log']);
+      expect(sourcemap.mappings).toEqual('AAAA,YAAY;;AAEZ,SAASA,UAAU,CAAC,EAAE;CACrBC,OAAO,CAACC,GAAG,CAAC,cAAc,CAAC;AAC5B');
+    }
+
+    pipe([
+      from.obj([file]),
+      identityMap(),
+      concat(assert),
+    ], done);
+  });
+
+  it('adds a valid source map for CSS', function(done) {
+    var file = makeFile();
+    file.extname = '.css';
+    file.contents = cssContent;
+
+    function assert(files) {
+      expect(files.length).toEqual(1);
+
+      var sourcemap = files[0].sourceMap;
+      expect(sourcemap).toExist();
+      expect(sourcemap.version).toEqual('3');
+      expect(sourcemap.sources[0]).toBe('helloworld.css');
+      expect(sourcemap.sourcesContent[0]).toEqual(cssContent);
+      expect(sourcemap.names).toEqual([]);
+      expect(sourcemap.mappings).toBe('CAAC;EACC;EACA');
+    }
+
+    pipe([
+      from.obj([file]),
+      identityMap(),
+      concat(assert),
+    ], done);
+  });
+});