feat(hooks): Provide static getHook method for access to all html-web…

…pack-plugin hooks (#995)

BREAKING CHANGE: The html-webpack-plugin doesn't add its hooks to the compilation object anymore

README.md

@@ -308,8 +308,7 @@ function MyPlugin(options) {
 MyPlugin.prototype.apply = function (compiler) {
   compiler.hooks.compilation.tap('MyPlugin', (compilation) => {
     console.log('The compiler is starting a new compilation...');
-
-    compilation.hooks.htmlWebpackPluginAfterHtmlProcessing.tapAsync(
+    HtmlWebpackPlugin.getHooks(compilation).htmlWebpackPluginAfterHtmlProcessing.tapAsync(
       'MyPlugin',
       (data, cb) => {
         data.html += 'The Magic Footer'

index.js

@@ -21,14 +21,13 @@ const childCompiler = require('./lib/compiler.js');
 const prettyError = require('./lib/errors.js');
 const chunkSorter = require('./lib/chunksorter.js');
 const getHtmlWebpackPluginHooks = require('./lib/hooks.js').getHtmlWebpackPluginHooks;
-const getHtmlWebpackPluginHook = require('./lib/hooks.js').getHtmlWebpackPluginHook;
 
 const fsStatAsync = promisify(fs.stat);
 const fsReadFileAsync = promisify(fs.readFile);
 
 class HtmlWebpackPlugin {
   /**
-   * @param {Partial<HtmlWebpackPluginOptions>} options
+   * @param {Partial<HtmlWebpackPluginOptions>} [options]
    */
   constructor (options) {
     // Default options
@@ -60,10 +59,7 @@ class HtmlWebpackPlugin {
     this.childCompilationOutputName = undefined;
     this.assetJson = undefined;
     this.hash = undefined;
-    /**
-     * The major version number of this plugin
-     */
-    this.version = 4;
+    this.version = HtmlWebpackPlugin.version;
   }
 
   /**
@@ -173,7 +169,7 @@ class HtmlWebpackPlugin {
           })
         // Allow plugins to make changes to the assets before invoking the template
         // This only makes sense to use if `inject` is `false`
-          .then(compilationResult => getHtmlWebpackPluginHook(compilation, 'htmlWebpackPluginBeforeHtmlGeneration').promise({
+          .then(compilationResult => getHtmlWebpackPluginHooks(compilation).htmlWebpackPluginBeforeHtmlGeneration.promise({
             assets: assets,
             outputName: self.childCompilationOutputName,
             plugin: self
@@ -186,7 +182,7 @@ class HtmlWebpackPlugin {
         // Allow plugins to change the html before assets are injected
           .then(html => {
             const pluginArgs = {html: html, assets: assets, plugin: self, outputName: self.childCompilationOutputName};
-            return getHtmlWebpackPluginHook(compilation, 'htmlWebpackPluginBeforeHtmlProcessing').promise(pluginArgs);
+            return getHtmlWebpackPluginHooks(compilation).htmlWebpackPluginBeforeHtmlProcessing.promise(pluginArgs);
           })
           .then(result => {
             const html = result.html;
@@ -195,7 +191,7 @@ class HtmlWebpackPlugin {
             const assetTags = self.generateHtmlTagObjects(assets);
             const pluginArgs = {head: assetTags.head, body: assetTags.body, plugin: self, outputName: self.childCompilationOutputName};
             // Allow plugins to change the assetTag definitions
-            return getHtmlWebpackPluginHook(compilation, 'htmlWebpackPluginAlterAssetTags').promise(pluginArgs)
+            return getHtmlWebpackPluginHooks(compilation).htmlWebpackPluginAlterAssetTags.promise(pluginArgs)
               .then(result => self.postProcessHtml(html, assets, { body: result.body, head: result.head })
                 .then(html => _.extend(result, {html: html, assets: assets})));
           })
@@ -204,7 +200,7 @@ class HtmlWebpackPlugin {
             const html = result.html;
             const assets = result.assets;
             const pluginArgs = {html: html, assets: assets, plugin: self, outputName: self.childCompilationOutputName};
-            return getHtmlWebpackPluginHook(compilation, 'htmlWebpackPluginAfterHtmlProcessing').promise(pluginArgs)
+            return getHtmlWebpackPluginHooks(compilation).htmlWebpackPluginAfterHtmlProcessing.promise(pluginArgs)
               .then(result => result.html);
           })
           .catch(err => {
@@ -222,7 +218,7 @@ class HtmlWebpackPlugin {
               size: () => html.length
             };
           })
-          .then(() => getHtmlWebpackPluginHook(compilation, 'htmlWebpackPluginAfterEmit').promise({
+          .then(() => getHtmlWebpackPluginHooks(compilation).htmlWebpackPluginAfterEmit.promise({
             html: compilation.assets[self.childCompilationOutputName],
             outputName: self.childCompilationOutputName,
             plugin: self
@@ -697,4 +693,18 @@ function templateParametersGenerator (compilation, assets, options) {
     }
   };
 }
+
+// Statics:
+/**
+ * The major version number of this plugin
+ */
+HtmlWebpackPlugin.version = 4;
+
+/**
+ * A static helper to get the hooks for this plugin
+ *
+ * Usage: HtmlWebpackPlugin.getHook(compilation, 'HookName').tap('YourPluginName', () => { ... });
+ */
+HtmlWebpackPlugin.getHooks = getHtmlWebpackPluginHooks;
+
 module.exports = HtmlWebpackPlugin;

lib/compiler.js

@@ -22,7 +22,6 @@ const SingleEntryPlugin = require('webpack/lib/SingleEntryPlugin');
  * for multile HtmlWebpackPlugin instances to improve the compilation performance.
  */
 class HtmlWebpackChildCompiler {
-
   constructor () {
     /**
      * @type {string[]} templateIds

lib/hooks.js

@@ -5,18 +5,6 @@
 'use strict';
 /**
  * This file provides access to all public htmlWebpackPlugin hooks
- *
- * Usage:
- * ```js
- *  const getHtmlWebpackPluginHooks = require('html-webpack-plugin/lib/hooks').getHtmlWebpackPluginHooks;
- *
- *  compiler.hooks.compilation.tap('YOUR_PLUGIN_NAME', (compilation) => {
- *   const htmlWebpackPluginHooks = getHtmlWebpackPluginHooks(compilation);
- *   htmlWebpackPluginHooks.htmlWebpackPluginAfterEmit.tap('YOUR_PLUGIN_NAME', (pluginArgs) => {
- *     // your code
- *   });
- *  });
- * ```
  */
 
 /** @typedef {import("webpack/lib/Compilation.js")} WebpackCompilation */
@@ -75,18 +63,23 @@ const AsyncSeriesWaterfallHook = require('tapable').AsyncSeriesWaterfallHook;
   }} HtmlWebpackPluginHooks
   */
 
+/**
+ * @type {WeakMap<WebpackCompilation, HtmlWebpackPluginHooks>}}
+ */
+const htmlWebpackPluginHooksMap = new WeakMap();
+
 /**
  * Returns all public hooks of the html webpack plugin for the given compilation
  *
  * @param {WebpackCompilation} compilation
  * @returns {HtmlWebpackPluginHooks}
  */
 function getHtmlWebpackPluginHooks (compilation) {
-  /** @type {HtmlWebpackPluginHooks} */
-  const hooks = compilation.hooks;
+  let hooks = htmlWebpackPluginHooksMap.get(compilation);
   // Setup the hooks only once
-  if (!hooks.htmlWebpackPluginAfterEmit) {
-    attachHooksToCompilation(compilation);
+  if (hooks === undefined) {
+    hooks = createHtmlWebpackPluginHooks();
+    htmlWebpackPluginHooksMap.set(compilation, hooks);
   }
   return {
     htmlWebpackPluginBeforeHtmlGeneration: hooks.htmlWebpackPluginBeforeHtmlGeneration,
@@ -101,32 +94,18 @@ function getHtmlWebpackPluginHooks (compilation) {
  * Add hooks to the webpack compilation object to allow foreign plugins to
  * extend the HtmlWebpackPlugin
  *
- * @param {WebpackCompilation} compilation
+ * @returns {HtmlWebpackPluginHooks}
  */
-function attachHooksToCompilation (compilation) {
-  /** @type {HtmlWebpackPluginHooks} */
-  const hooks = compilation.hooks;
-  hooks.htmlWebpackPluginBeforeHtmlGeneration = new AsyncSeriesWaterfallHook(['pluginArgs']);
-  hooks.htmlWebpackPluginBeforeHtmlProcessing = new AsyncSeriesWaterfallHook(['pluginArgs']);
-  hooks.htmlWebpackPluginAlterAssetTags = new AsyncSeriesWaterfallHook(['pluginArgs']);
-  hooks.htmlWebpackPluginAfterHtmlProcessing = new AsyncSeriesWaterfallHook(['pluginArgs']);
-  hooks.htmlWebpackPluginAfterEmit = new AsyncSeriesWaterfallHook(['pluginArgs']);
+function createHtmlWebpackPluginHooks () {
+  return {
+    htmlWebpackPluginBeforeHtmlGeneration: new AsyncSeriesWaterfallHook(['pluginArgs']),
+    htmlWebpackPluginBeforeHtmlProcessing: new AsyncSeriesWaterfallHook(['pluginArgs']),
+    htmlWebpackPluginAlterAssetTags: new AsyncSeriesWaterfallHook(['pluginArgs']),
+    htmlWebpackPluginAfterHtmlProcessing: new AsyncSeriesWaterfallHook(['pluginArgs']),
+    htmlWebpackPluginAfterEmit: new AsyncSeriesWaterfallHook(['pluginArgs'])
+  };
 }
 
-/**
- * Small workaround helper to work around https://github.com/Microsoft/TypeScript/issues/1178
- * Returns the hook of the given name
- *
- * @type {
-    <T extends keyof HtmlWebpackPluginHooks>(compilation: WebpackCompilation, hookName: T) => HtmlWebpackPluginHooks[T]
-   }
- */
-const getHtmlWebpackPluginHook = (compilation, hookName) => {
-  const hooks = getHtmlWebpackPluginHooks(compilation);
-  return /** @type {any} */hooks[hookName];
-};
-
 module.exports = {
-  getHtmlWebpackPluginHooks,
-  getHtmlWebpackPluginHook
+  getHtmlWebpackPluginHooks
 };

spec/BasicSpec.js

@@ -136,7 +136,7 @@ function getChunksInfoFromStats (stats) {
 function tapCompilationEvent (compilation, eventName, handler) {
   // Webpack 4 has a new interface
   if (compilation.hooks) {
-    return compilation.hooks[trainCaseToCamelCase(eventName)].tapAsync(
+    return HtmlWebpackPlugin.getHooks(compilation)[trainCaseToCamelCase(eventName)].tapAsync(
       'AsyncPlugin' + tapCompilationEvent.counter++,
       handler
     );

spec/ExampleSpec.js

@@ -3,7 +3,7 @@
  * and matches them against their dist folder
  */
 
- /* eslint-env jasmine */
+/* eslint-env jasmine */
 'use strict';
 
 var path = require('path');