Pass entrypoints param to generate function (#192)

* Pass `entrypoints` param to `generate` function

* Fix `entrypoints` compatibility with Webpack 4+

Author: samuelmeuli

README.md

@@ -108,8 +108,8 @@ Sort files before they are passed to `generate`. [FileDescriptor typings](#filed
 
 ### `options.generate`
 
-Type: `Function(Object, FileDescriptor): Object`<br>
-Default: `(seed, files) => files.reduce((manifest, {name, path}) => ({...manifest, [name]: path}), seed)`
+Type: `Function(Object, FileDescriptor, string[]): Object`<br>
+Default: `(seed, files, entrypoints) => 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)
 

lib/plugin.js

@@ -161,7 +161,18 @@ ManifestPlugin.prototype.apply = function(compiler) {
 
     var manifest;
     if (this.opts.generate) {
-      manifest = this.opts.generate(seed, files);
+      const entrypointsArray = Array.from(
+        compilation.entrypoints instanceof Map ?
+          // Webpack 4+
+          compilation.entrypoints.entries() :
+          // Webpack 3
+          Object.entries(compilation.entrypoints)
+      );
+      const entrypoints = entrypointsArray.reduce((e, [name, entrypoint]) => ({
+        ...e,
+        [name]: entrypoint.getFiles()
+      }), {});
+      manifest = this.opts.generate(seed, files, entrypoints);
     } else {
       manifest = files.reduce(function (manifest, file) {
         manifest[file.name] = file.path;

spec/plugin.spec.js

@@ -745,6 +745,44 @@ describe('ManifestPlugin', function() {
     });
   });
 
+  it('should generate manifest with "entrypoints" key', done => {
+    webpackCompile({
+      context: __dirname,
+      entry: {
+        one: './fixtures/file.js',
+        two: './fixtures/file-two.js'
+      }
+    },
+    {
+      manifestOptions: {
+        generate: (seed, files, entrypoints) => {
+          const manifestFiles = files.reduce((manifest, { name, path }) => ({
+            ...manifest,
+            [name]: path
+          }), seed);
+          return {
+            files: manifestFiles,
+            entrypoints
+          };
+        }
+      }
+    },
+    (manifest, stats) => {
+      expect(manifest).toEqual({
+        entrypoints: {
+          one: ['one.js'],
+          two: ['two.js']
+        },
+        files: {
+          'one.js': 'one.js',
+          'two.js': 'two.js'
+        }
+      });
+
+      done();
+    });
+  });
+
   describe('with CopyWebpackPlugin', function () {
     it('works when including copied assets', function (done) {
       webpackCompile({