feat: Added ability to adjust plugin processAssets hook stage (#262)

Author: tomlagier

README.md

@@ -230,6 +230,15 @@ This plugin supports the following hooks via the `getCompilerHooks` export; `aft
 
 Returns: `{ afterEmit: SyncWaterfallHook, beforeEmit: SyncWaterfallHook }`
 
+### `assetHookStage`
+
+Type: `Number`
+Default: `Infinity`
+
+If you need to consume the output of this plugin in another plugin, it can be useful to adjust the stage at which the manifest is generated. Pass a new stage to `assetHookStage` to change when the manifest is generated. See the [docs on `processAssets`](https://webpack.js.org/api/compilation-hooks/#list-of-asset-processing-stages) for more detail.
+
+Note: any files added to the compilation after the stage specified will not be included in the manifest.
+
 #### Usage
 
 ```js

src/index.ts

@@ -14,6 +14,7 @@ export type Manifest = Record<string, any>;
 
 export interface InternalOptions {
   [key: string]: any;
+  assetHookStage: number;
   basePath: string;
   fileName: string;
   filter: (file: FileDescriptor) => Boolean;
@@ -37,6 +38,7 @@ export interface InternalOptions {
 export type ManifestPluginOptions = Partial<InternalOptions>;
 
 const defaults = {
+  assetHookStage: Infinity,
   basePath: '',
   fileName: 'manifest.json',
   filter: null,
@@ -84,7 +86,7 @@ class WebpackManifestPlugin implements WebpackPluginInstance {
     const normalModuleLoader = normalModuleLoaderHook.bind(this, { moduleAssets });
     const hookOptions = {
       name: 'WebpackManifestPlugin',
-      stage: Infinity
+      stage: this.options.assetHookStage
     };
 
     compiler.hooks.compilation.tap(hookOptions, (compilation) => {

test/unit/options.js

@@ -5,6 +5,8 @@ const CopyPlugin = require('copy-webpack-plugin');
 const DependencyExtractionWebpackPlugin = require('@wordpress/dependency-extraction-webpack-plugin');
 const del = require('del');
 
+const webpack = require('webpack');
+
 const { compile } = require('../helpers/unit');
 
 const outputPath = join(__dirname, '../output/options');
@@ -141,3 +143,55 @@ test('useLegacyEmit', async (t) => {
 
   t.snapshot(manifest);
 });
+
+test('assetHookStage', async (t) => {
+  const FIRST_PROCESS_ASSETS_STAGE = 0;
+  const SECOND_PROCESS_ASSETS_STAGE = 1;
+  let assets;
+
+  class LastStagePlugin {
+    /* eslint-disable class-methods-use-this */
+    apply(compiler) {
+      const isWebpack4 = webpack.version.startsWith('4');
+
+      const callback = (compilation) => {
+        // We'll check for our manifest being included in the assets of this invocation
+        assets = Object.keys(isWebpack4 ? compilation.assets : compilation);
+      };
+
+      const hookOptions = {
+        name: 'LastStagePlugin',
+        // Make sure our plugin is scheduled to run after the manifest plugin
+        stage: SECOND_PROCESS_ASSETS_STAGE
+      };
+
+      if (isWebpack4) {
+        compiler.hooks.emit.tap(hookOptions, callback);
+      } else {
+        compiler.hooks.thisCompilation.tap(hookOptions, (compilation) => {
+          compilation.hooks.processAssets.tap(hookOptions, callback);
+        });
+      }
+    }
+    /* eslint-enable class-methods-use-this */
+  }
+
+  const config = {
+    context: __dirname,
+    entry: {
+      main: '../fixtures/file.js'
+    },
+    output: {
+      filename: '[name].js',
+      path: join(outputPath, 'assetHookStage')
+    },
+    plugins: [new LastStagePlugin()]
+  };
+
+  // Ensure we register the manifest plugin to run first.
+  const { manifest } = await compile(config, t, { assetHookStage: FIRST_PROCESS_ASSETS_STAGE });
+
+  t.snapshot(manifest);
+  const laterPluginHasManifest = assets.includes('manifest.json');
+  t.is(laterPluginHasManifest, true);
+});

test/unit/snapshots/options.js.md

@@ -65,3 +65,11 @@ Generated by [AVA](https://avajs.dev).
       'main.js': 'main.js',
       'main.json': 'main.asset.json',
     }
+
+## assetHookStage
+
+> Snapshot 1
+
+    {
+      'main.js': 'main.js',
+    }