index.js

var assert = require('assert');
var PLUGIN_NAME = 'HtmlWebpackEventPlugin';

function HtmlWebpackEventPlugin(options) {
  assert.equal(options, undefined, PLUGIN_NAME + ' does not accept any options');
}

HtmlWebpackEventPlugin.prototype.apply = function (compiler) {
  var self = this;

  // webpack 4
  if (compiler.hooks) {
    compiler.hooks.compilation.tap(PLUGIN_NAME, function (compilation) {
      // Let plugins alter the chunks and the chunk sorting
      compilation.hooks.htmlWebpackPluginAlterChunks.tap(PLUGIN_NAME, function (chunks, htmlPluginData) {
        var eventFun = htmlPluginData ? htmlPluginData.plugin.options.alterChunks : null;
        var ret = self.callEventFun(eventFun, htmlPluginData, chunks);
        return ret.data;
      });

      // Allow plugins to make changes to the assets before invoking the template
      // This only makes sense to use if `inject` is `false`
      compilation.hooks.htmlWebpackPluginBeforeHtmlGeneration.tapAsync(PLUGIN_NAME, function (htmlPluginData, callback) {
        var eventFun = htmlPluginData ? htmlPluginData.plugin.options.beforeHtmlGeneration : null;
        var ret = self.callEventFun(eventFun, htmlPluginData, htmlPluginData);
        callback(ret.error, ret.data);
      });

      // Allow plugins to change the html before assets are injected
      compilation.hooks.htmlWebpackPluginBeforeHtmlProcessing.tapAsync(PLUGIN_NAME, function (htmlPluginData, callback) {
        var eventFun = htmlPluginData ? htmlPluginData.plugin.options.beforeHtmlProcessing : null;
        var ret = self.callEventFun(eventFun, htmlPluginData, htmlPluginData);
        callback(ret.error, ret.data);
      });

      // Allow plugins to change the assetTag definitions
      compilation.hooks.htmlWebpackPluginAlterAssetTags.tapAsync(PLUGIN_NAME, function (htmlPluginData, callback) {
        var eventFun = htmlPluginData ? htmlPluginData.plugin.options.alterAssetTags : null;
        var ret = self.callEventFun(eventFun, htmlPluginData, htmlPluginData);
        callback(ret.error, ret.data);
      });

      // Allow plugins to change the html after assets are injected
      compilation.hooks.htmlWebpackPluginAfterHtmlProcessing.tapAsync(PLUGIN_NAME, function (htmlPluginData, callback) {
        var eventFun = htmlPluginData ? htmlPluginData.plugin.options.afterHtmlProcessing : null;
        var ret = self.callEventFun(eventFun, htmlPluginData, htmlPluginData);
        callback(ret.error, ret.data);
      });

      // Let other plugins know that we are done:
      compilation.hooks.htmlWebpackPluginAfterEmit.tapAsync(PLUGIN_NAME, function (htmlPluginData, callback) {
        // htmlPluginData === undefined
        var eventFun = htmlPluginData ? htmlPluginData.plugin.options.afterEmit : null;
        var ret = self.callEventFun(eventFun, htmlPluginData, htmlPluginData);
        callback(ret.error, ret.data);
      });
    });
  }
  else {
    compiler.plugin('compilation', function (compilation) {
      // Let plugins alter the chunks and the chunk sorting
      compilation.plugin('html-webpack-plugin-alter-chunks', function (chunks, htmlPluginData) {
        var eventFun = htmlPluginData ? htmlPluginData.plugin.options.alterChunks : null;
        var ret = self.callEventFun(eventFun, htmlPluginData, chunks);
        return ret.data;
      });

      // Allow plugins to make changes to the assets before invoking the template
      // This only makes sense to use if `inject` is `false`
      compilation.plugin('html-webpack-plugin-before-html-generation', function (htmlPluginData, callback) {
        var eventFun = htmlPluginData ? htmlPluginData.plugin.options.beforeHtmlGeneration : null;
        var ret = self.callEventFun(eventFun, htmlPluginData, htmlPluginData);
        callback(ret.error, ret.data);
      });

      // Allow plugins to change the html before assets are injected
      compilation.plugin('html-webpack-plugin-before-html-processing', function (htmlPluginData, callback) {
        var eventFun = htmlPluginData ? htmlPluginData.plugin.options.beforeHtmlProcessing : null;
        var ret = self.callEventFun(eventFun, htmlPluginData, htmlPluginData);
        callback(ret.error, ret.data);
      });

      // Allow plugins to change the assetTag definitions
      compilation.plugin('html-webpack-plugin-alter-asset-tags', function (htmlPluginData, callback) {
        var eventFun = htmlPluginData ? htmlPluginData.plugin.options.alterAssetTags : null;
        var ret = self.callEventFun(eventFun, htmlPluginData, htmlPluginData);
        callback(ret.error, ret.data);
      });

      // Allow plugins to change the html after assets are injected
      compilation.plugin('html-webpack-plugin-after-html-processing', function (htmlPluginData, callback) {
        var eventFun = htmlPluginData ? htmlPluginData.plugin.options.afterHtmlProcessing : null;
        var ret = self.callEventFun(eventFun, htmlPluginData, htmlPluginData);
        callback(ret.error, ret.data);
      });

      // Let other plugins know that we are done:
      compilation.plugin('html-webpack-plugin-after-emit', function (htmlPluginData, callback) {
        // htmlPluginData === undefined
        var eventFun = htmlPluginData ? htmlPluginData.plugin.options.afterEmit : null;
        var ret = self.callEventFun(eventFun, htmlPluginData, htmlPluginData);
        callback(ret.error, ret.data);
      });
    });
  }
};

HtmlWebpackEventPlugin.prototype.callEventFun = function (eventFun, htmlPluginData, defaultData) {
  var ret = {
    error: null,
    data: null
  };
  if (typeof eventFun === 'function') {
    try {
      ret.data = eventFun(htmlPluginData, defaultData);
    } catch (error) {
      ret.error = error;
    }
  } else {
    ret.data = defaultData;
  }
  return ret;
};

module.exports = HtmlWebpackEventPlugin;