WIP - add extractor, generate snippet_data

node_modules/webpack-stats-plugin/lib/stats-writer-plugin.js

@@ -0,0 +1,92 @@
+/**
+ * Stats writer module.
+ *
+ * Stats can be a string or array (we"ll have array from using source maps):
+ *
+ * ```js
+ * "assetsByChunkName": {
+ *   "main": [
+ *     "cd6371d4131fbfbefaa7.bundle.js",
+ *     "../js-map/cd6371d4131fbfbefaa7.bundle.js.map"
+ *   ]
+ * },
+ * ```
+ *
+ * **Note**: The stats object is **big**. It includes the entire source included
+ * in a bundle. Thus, we default `opts.fields` to `["assetsByChunkName"]` to
+ * only include those. However, if you want the _whole thing_ (maybe doing an
+ * `opts.transform` function), then you can set `fields: null` in options to
+ * get **all** of the stats object.
+ *
+ * See:
+ * - http://webpack.github.io/docs/long-term-caching.html#get-filenames-from-stats
+ * - https://github.com/webpack/docs/wiki/node.js-api#stats
+ *
+ * **`filename`**: The `opts.filename` option can be a file name or path relative to
+ * `output.path` in webpack configuration. It should not be absolute.
+ *
+ * **`transform`**: By default, the retrieved stats object is `JSON.stringify`'ed
+ * but by supplying an alternate transform you can target _any_ output format.
+ * See [`demo/webpack.config.js`](demo/webpack.config.js) for various examples
+ * including Markdown output.
+ *
+ * - **Warning**: The output of `transform` should be a `String`, not an object.
+ *   On Node `v4.x` if you return a real object in `transform`, then webpack
+ *   will break with a `TypeError` (See #8). Just adding a simple
+ *   `JSON.stringify()` around your object is usually what you need to solve
+ *   any problems.
+ *
+ * @param {Object}   opts           options
+ * @param {String}   opts.filename  output file name (Default: "stat.json")
+ * @param {Array}    opts.fields    fields of stats obj to keep (Default: \["assetsByChunkName"\])
+ * @param {Function} opts.transform transform stats obj (Default: `JSON.stringify()`)
+ *
+ * @api public
+ */
+function StatsWriterPlugin(opts) {
+  opts = opts || {};
+  this.opts = {};
+  this.opts.filename = opts.filename || "stats.json";
+  this.opts.fields = typeof opts.fields !== "undefined" ? opts.fields : ["assetsByChunkName"];
+  this.opts.transform = opts.transform || function (data) { return JSON.stringify(data, null, 2); };
+}
+
+StatsWriterPlugin.prototype = {
+  constructor: StatsWriterPlugin,
+
+  apply: function (compiler) {
+    var self = this;
+    compiler.plugin("emit", function (curCompiler, callback) {
+      // Get stats.
+      // **Note**: In future, could pass something like `{ showAssets: true }`
+      // to the `getStats()` function for more limited object returned.
+      var stats = curCompiler.getStats().toJson();
+
+      // Filter to fields.
+      if (self.opts.fields) {
+        stats = self.opts.fields.reduce(function (memo, key) {
+          memo[key] = stats[key];
+          return memo;
+        }, {});
+      }
+
+      // Transform to string.
+      var statsStr = self.opts.transform(stats, {
+        compiler: curCompiler
+      });
+
+      curCompiler.assets[self.opts.filename] = {
+        source: function () {
+          return statsStr;
+        },
+        size: function () {
+          return statsStr.length;
+        }
+      };
+
+      callback();
+    });
+  }
+};
+
+module.exports = StatsWriterPlugin;