Implementation?

README.md

@@ -1,2 +1,34 @@
-# comment
+# @gulp-sourcemaps/comment
+
+[![NPM version][npm-image]][npm-url] [![Downloads][downloads-image]][npm-url] [![Build Status][travis-image]][travis-url] [![AppVeyor Build Status][appveyor-image]][appveyor-url] [![Coveralls Status][coveralls-image]][coveralls-url]
+
 Gulp plugin for working with the sourceMappingURL comment of a file.
+
+## Example
+
+```js
+TODO
+```
+
+## API
+
+### TODO
+
+## License
+
+MIT
+
+[vinyl-url]: https://github.com/gulpjs/vinyl
+
+[downloads-image]: http://img.shields.io/npm/dm/@gulp-sourcemaps/comment.svg
+[npm-url]: https://npmjs.org/package/@gulp-sourcemaps/comment
+[npm-image]: http://img.shields.io/npm/v/@gulp-sourcemaps/comment.svg
+
+[travis-url]: https://travis-ci.org/gulp-sourcemaps/comment
+[travis-image]: http://img.shields.io/travis/gulp-sourcemaps/comment.svg?label=travis-ci
+
+[appveyor-url]: https://ci.appveyor.com/project/phated/comment
+[appveyor-image]: https://img.shields.io/appveyor/ci/phated/comment.svg?label=appveyor
+
+[coveralls-url]: https://coveralls.io/r/gulp-sourcemaps/comment
+[coveralls-image]: http://img.shields.io/coveralls/gulp-sourcemaps/comment.svg

index.js

@@ -0,0 +1,106 @@
+'use strict';
+
+var path = require('path');
+var through = require('through2');
+var convert = require('convert-source-map');
+var normalize = require('normalize-path');
+
+function processInline(contents, mapper) {
+  var sourceMappingURL = convert.getCommentValue(contents);
+
+  var result = mapper(sourceMappingURL);
+
+  if (!result) {
+    return convert.removeComments(contents);
+  }
+
+  if (result !== sourceMappingURL) {
+    // TODO: use the same comment type as original
+    // TODO: we don't want to parse/convert so this works but should be named different
+    result = convert.generateMapFileComment(result);
+    // TODO: add `replaceComments` to convert-source-map
+    return contents.replace(convert.commentRegex, result);
+  }
+}
+
+function processExternal(contents, mapper) {
+  var sourceMappingURL = convert.getMapFileCommentValue(contents);
+
+  var result = mapper(sourceMappingURL);
+
+  if (!result) {
+    return convert.removeMapFileComments(contents);
+  }
+
+  if (result !== sourceMappingURL) {
+    // TODO: use the same comment type as original
+    result = convert.generateMapFileComment(result);
+    // TODO: add `replaceMapFileComments` to convert-source-map
+    return contents.replace(convert.mapFileCommentRegex, result);
+  }
+}
+
+function comment(mapFn) {
+
+  function transform(file, _, cb) {
+    // TODO: should this error? Probably not
+    if (!file.isBuffer()) {
+      return cb(null, file);
+    }
+
+    var contents = file.contents.toString();
+
+    var hasInlineSourcemap = convert.commentRegex.test(contents);
+    var hasExternalSourcemap = convert.mapFileCommentRegex.test(contents);
+
+    if (!hasInlineSourcemap && !hasExternalSourcemap) {
+      return cb(null, file);
+    }
+
+    function mapper(sourceMappingURL) {
+      var result = sourceMappingURL;
+      if (typeof mapFn === 'function') {
+        result = mapFn(sourceMappingURL, file);
+      }
+
+      // This is inverted because hasExternalSourcemap covers inline also
+      if (hasInlineSourcemap || !result) {
+        return result;
+      }
+
+      return normalize(result);
+    }
+
+    // Always one of the 2 because we bail if neither
+    var processor = hasInlineSourcemap ? processInline : processExternal;
+
+    var result = processor(contents, mapper);
+
+    if (result) {
+      file.contents = new Buffer(result);
+    }
+
+    return cb(null, file);
+  }
+
+  return through.obj(transform);
+}
+
+function prefix(str) {
+  // TODO: should this somehow check if it is a path vs data-uri?
+  return comment(function(sourceMappingURL) {
+    // TODO: url instead of path?
+    return str + path.join('/', sourceMappingURL);
+  });
+}
+comment.prefix = prefix;
+
+function remove() {
+  return comment(function() {
+    // Returning anything falsey removes the comment
+    return null;
+  });
+}
+comment.remove = remove;
+
+module.exports = comment;

package.json

@@ -17,13 +17,17 @@
     "index.js"
   ],
   "scripts": {
-    "lint": "eslint . && jscs index.js test/",
+    "lint": "eslint . && jscs index.js test/index.js",
     "pretest": "npm run lint",
     "test": "mocha --async-only",
     "cover": "istanbul cover _mocha --report lcovonly",
     "coveralls": "npm run cover && istanbul-coveralls"
   },
-  "dependencies": {},
+  "dependencies": {
+    "convert-source-map": "thlorenz/convert-source-map#comment-values",
+    "normalize-path": "^2.0.1",
+    "through2": "^2.0.3"
+  },
   "devDependencies": {
     "eslint": "^1.7.3",
     "eslint-config-gulp": "^2.0.0",

test/fixtures/helloworld.js

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