Add reference to webpack.Compilation to generate

README.md

@@ -56,7 +56,7 @@ module.exports = {
 Type: `String`<br>
 Default: `manifest.json`
 
-By default the plugin will emit `manifest.json` to your output directory. Can override with an absolute path. 
+By default the plugin will emit `manifest.json` to your output directory. Can override with an absolute path.
 
 ### `options.publicPath`
 
@@ -108,10 +108,12 @@ Sort files before they are passed to `generate`. [FileDescriptor typings](#filed
 
 ### `options.generate`
 
-Type: `Function(Object, FileDescriptor, string[]): Object`<br>
-Default: `(seed, files, entrypoints) => files.reduce((manifest, {name, path}) => ({...manifest, [name]: path}), seed)`
+Type: `Function(Object, FileDescriptor, string[], webpack.Compilation): Object`<br>
+Default: `(seed, files, entrypoints, compilation) => files.reduce((manifest, {name, path}) => ({...manifest, [name]: path}), seed)`
 
-Create the manifest. It can return anything as long as it's serialisable by `JSON.stringify`. [FileDescriptor typings](#filedescriptor)
+Create the manifest. It can return anything as long as it's serialisable by `JSON.stringify`. [FileDescriptor typings](#filedescriptor).
+
+The `compilation` object is a reference to the [Webpack Compilation](https://webpack.js.org/api/compilation-object/) object and allows you to extend this package's functionalitiy with for example Integrity checking. See [`./examples/integrity-manifest.js`](./examples/integrity-manifest.js) for an example.
 
 ### `options.serialize`
 

examples/integrity-manifest.js

@@ -0,0 +1,36 @@
+const ManifestPlugin = require('webpack-manifest-plugin');
+const crypto = require('crypto');
+
+/**
+ * This example returns a manifest object containing
+ * each path with a integrity hash:
+ *
+ * {
+ *  "main.bd17d3636cb.js": "sha256-4a97d363df66cd8a4f4bd16cb80026bcf50fd9233761de21c34a5b55293345d2"
+ * }
+ *
+ * It can be used in combination with for example the
+ * webpack-subresource-integrity package.
+ */
+module.exports = {
+  plugins: [
+    new ManifestPlugin({
+      generate: (seed, files, entrypoints, compilation) => {
+        return files.reduce((manifest, { path, name }) => {
+          const compilationAsset = compilation.assets[name];
+          // Use 'integrity' as set by webpack-subresource-integrity or
+          // generate a new hash
+          const integrity = compilationAsset ? compilationAsset.integrity || createIntegrityHash(compilationAsset.source()) : null;
+          return { ...manifest, [path]: integrity };
+        }, seed);
+      }
+    }),
+  ]
+};
+
+function createIntegrityHash(content, algorithm = 'sha256') {
+  const hash = crypto.createHash(algorithm)
+    .update(content, 'utf-8')
+    .digest('hex');
+  return algorithm + '-' + hash;
+}

lib/plugin.js

@@ -23,7 +23,7 @@ function ManifestPlugin(opts) {
     map: null,
     generate: null,
     sort: null,
-    serialize: function(manifest) {
+    serialize: function (manifest) {
       return JSON.stringify(manifest, null, 2);
     },
   }, opts || {});
@@ -41,7 +41,7 @@ ManifestPlugin.getCompilerHooks = (compiler) => {
   return hooks;
 }
 
-ManifestPlugin.prototype.getFileType = function(str) {
+ManifestPlugin.prototype.getFileType = function (str) {
   str = str.replace(/\?.*/, '');
   var split = str.split('.');
   var ext = split.pop();
@@ -51,7 +51,7 @@ ManifestPlugin.prototype.getFileType = function(str) {
   return ext;
 };
 
-ManifestPlugin.prototype.apply = function(compiler) {
+ManifestPlugin.prototype.apply = function (compiler) {
   var moduleAssets = {};
 
   var outputFolder = compiler.options.output.path;
@@ -68,23 +68,23 @@ ManifestPlugin.prototype.apply = function(compiler) {
   };
 
 
-  var emit = function(compilation, compileCallback) {
+  var emit = function (compilation, compileCallback) {
     const emitCount = emitCountMap.get(outputFile) - 1
     emitCountMap.set(outputFile, emitCount);
 
     var seed = this.opts.seed || {};
 
     var publicPath = this.opts.publicPath != null ? this.opts.publicPath : compilation.options.output.publicPath;
     var stats = compilation.getStats().toJson({
-        // Disable data generation of everything we don't use
-        all: false,
-        // Add asset Information
-        assets: true,
-        // Show cached assets (setting this to `false` only shows emitted files)
-        cachedAssets: true,
+      // Disable data generation of everything we don't use
+      all: false,
+      // Add asset Information
+      assets: true,
+      // Show cached assets (setting this to `false` only shows emitted files)
+      cachedAssets: true,
     });
 
-    var files = compilation.chunks.reduce(function(files, chunk) {
+    var files = compilation.chunks.reduce(function (files, chunk) {
       return chunk.files.reduce(function (files, path) {
         var name = chunk.name ? chunk.name : null;
 
@@ -152,7 +152,7 @@ ManifestPlugin.prototype.apply = function(compiler) {
     // Append optional basepath onto all references.
     // This allows output path to be reflected in the manifest.
     if (this.opts.basePath) {
-      files = files.map(function(file) {
+      files = files.map(function (file) {
         file.name = this.opts.basePath + file.name;
         return file;
       }.bind(this));
@@ -162,7 +162,7 @@ ManifestPlugin.prototype.apply = function(compiler) {
       // Similar to basePath but only affects the value (similar to how
       // output.publicPath turns require('foo/bar') into '/public/foo/bar', see
       // https://github.com/webpack/docs/wiki/configuration#outputpublicpath
-      files = files.map(function(file) {
+      files = files.map(function (file) {
         file.path = publicPath + file.path;
         return file;
       }.bind(this));
@@ -195,7 +195,7 @@ ManifestPlugin.prototype.apply = function(compiler) {
         (e, [name, entrypoint]) => Object.assign(e, { [name]: entrypoint.getFiles() }),
         {}
       );
-      manifest = this.opts.generate(seed, files, entrypoints);
+      manifest = this.opts.generate(seed, files, entrypoints, compilation);
     } else {
       manifest = files.reduce(function (manifest, file) {
         manifest[file.name] = file.path;
@@ -208,10 +208,10 @@ ManifestPlugin.prototype.apply = function(compiler) {
       var output = this.opts.serialize(manifest);
 
       compilation.assets[outputName] = {
-        source: function() {
+        source: function () {
           return output;
         },
-        size: function() {
+        size: function () {
           return output.length;
         }
       };
@@ -228,7 +228,7 @@ ManifestPlugin.prototype.apply = function(compiler) {
     }
   }.bind(this);
 
-  function beforeRun (compiler, callback) {
+  function beforeRun(compiler, callback) {
     let emitCount = emitCountMap.get(outputFile) || 0;
     emitCountMap.set(outputFile, emitCount + 1);