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Dll scope hoisting

This example demonstrates the usage of entryOnly option in combination with module concatenation / scope hoisting.

By default, DllPlugin exposes all the modules referenced in the bundle as separate entries. The manifest includes the individual modules available for use by DllReferencePlugin. Since all the modules are being accounted for, this prevents advanced optimizations such as tree shaking.

The entryOnly flag tells DllPlugin to only expose the modules which are configured as entry points; this affects both the manifest and the resulting bundle. Since some of the modules are no longer included in the "public contract" of the Dll, they can be optimized by merging (concatenating) multiple modules together or removing unused code. This allows taking advantage of tree shaking (scope hoisting and dead code removal) optimizations.

In this example, only example.js module is exposed, since it's the entry point. Modules a.js and b.js are concatenated into example.js. Module cjs.js is left as is since it's in CommonJS format.

The manifest includes example.js as the only exposed module and lists the exports as ["a","b","c"] from the corresponding modules a.js, b.js, and cjs.js. None of the other modules are exposed.

Also, see tree shaking and scope hoisting example.

example.js

export { a, b } from "./a";
export { c } from "./cjs";

webpack.config.js

var path = require("path");
var webpack = require("../../");

module.exports = {
	// mode: "development" || "production",
	entry: {
		dll: ["./example"]
	},
	output: {
		path: path.join(__dirname, "dist"),
		filename: "[name].js",
		library: "[name]_[fullhash]"
	},
	optimization: {
		concatenateModules: true // this is enabled by default in production mode
	},
	plugins: [
		new webpack.DllPlugin({
			path: path.join(__dirname, "dist", "[name]-manifest.json"),
			name: "[name]_[fullhash]",
			entryOnly: true
		})
	]
};

dist/dll.js

var dll_84b3c692d890d26bb885;dll_84b3c692d890d26bb885 =
/******/ (() => { // webpackBootstrap
/******/ 	var __webpack_modules__ = ([
/* 0 */
/*!***************!*\
  !*** dll dll ***!
  \***************/
/*! unknown exports (runtime-defined) */
/*! runtime requirements: __webpack_require__, module */
/*! ModuleConcatenation bailout: Module Concatenation is not implemented for DllModule */
/***/ ((module, __unused_webpack_exports, __webpack_require__) => {

module.exports = __webpack_require__;

/***/ }),
/* 1 */
/*!********************************!*\
  !*** ./example.js + 2 modules ***!
  \********************************/
/*! namespace exports */
/*! export a [provided] [no usage info] [missing usage info prevents renaming] -> ./a.js .a */
/*! export b [provided] [no usage info] [missing usage info prevents renaming] -> ./b.js .b */
/*! export c [provided] [no usage info] [missing usage info prevents renaming] -> ./cjs.js .c */
/*! other exports [not provided] [no usage info] */
/*! runtime requirements: __webpack_require__.r, __webpack_exports__, __webpack_require__.d, __webpack_require__, __webpack_require__.* */
/*! ModuleConcatenation bailout: Cannot concat with ./cjs.js: Module is not an ECMAScript module */
/***/ ((__unused_webpack_module, __webpack_exports__, __webpack_require__) => {

"use strict";
// ESM COMPAT FLAG
__webpack_require__.r(__webpack_exports__);

// EXPORTS
__webpack_require__.d(__webpack_exports__, {
  "a": () => /* reexport */ a,
  "b": () => /* reexport */ b,
  "c": () => /* reexport */ cjs.c
});

// CONCATENATED MODULE: ./b.js
// module b
function b() {
	return "b";
}

// CONCATENATED MODULE: ./a.js
// module a
var a = "a";


// EXTERNAL MODULE: ./cjs.js
var cjs = __webpack_require__(2);
// CONCATENATED MODULE: ./example.js




/***/ }),
/* 2 */
/*!****************!*\
  !*** ./cjs.js ***!
  \****************/
/*! default exports */
/*! export c [provided] [no usage info] [missing usage info prevents renaming] */
/*! other exports [not provided] [no usage info] */
/*! runtime requirements: __webpack_exports__ */
/*! ModuleConcatenation bailout: Module is not an ECMAScript module */
/***/ ((__unused_webpack_module, exports) => {

// module cjs (commonjs)
exports.c = "c";


/***/ })
/******/ 	]);

/* webpack runtime code */

/************************************************************************/
/******/ 	// The module cache
/******/ 	var __webpack_module_cache__ = {};
/******/ 	
/******/ 	// The require function
/******/ 	function __webpack_require__(moduleId) {
/******/ 		// Check if module is in cache
/******/ 		if(__webpack_module_cache__[moduleId]) {
/******/ 			return __webpack_module_cache__[moduleId].exports;
/******/ 		}
/******/ 		// Create a new module (and put it into the cache)
/******/ 		var module = __webpack_module_cache__[moduleId] = {
/******/ 			// no module.id needed
/******/ 			// no module.loaded needed
/******/ 			exports: {}
/******/ 		};
/******/ 	
/******/ 		// Execute the module function
/******/ 		__webpack_modules__[moduleId](module, module.exports, __webpack_require__);
/******/ 	
/******/ 		// Return the exports of the module
/******/ 		return module.exports;
/******/ 	}
/******/ 	
/************************************************************************/
/******/ 	/* webpack/runtime/define property getters */
/******/ 	(() => {
/******/ 		// define getter functions for harmony exports
/******/ 		__webpack_require__.d = (exports, definition) => {
/******/ 			for(var key in definition) {
/******/ 				if(__webpack_require__.o(definition, key) && !__webpack_require__.o(exports, key)) {
/******/ 					Object.defineProperty(exports, key, { enumerable: true, get: definition[key] });
/******/ 				}
/******/ 			}
/******/ 		};
/******/ 	})();
/******/ 	
/******/ 	/* webpack/runtime/hasOwnProperty shorthand */
/******/ 	(() => {
/******/ 		__webpack_require__.o = (obj, prop) => Object.prototype.hasOwnProperty.call(obj, prop)
/******/ 	})();
/******/ 	
/******/ 	/* webpack/runtime/make namespace object */
/******/ 	(() => {
/******/ 		// define __esModule on exports
/******/ 		__webpack_require__.r = (exports) => {
/******/ 			if(typeof Symbol !== 'undefined' && Symbol.toStringTag) {
/******/ 				Object.defineProperty(exports, Symbol.toStringTag, { value: 'Module' });
/******/ 			}
/******/ 			Object.defineProperty(exports, '__esModule', { value: true });
/******/ 		};
/******/ 	})();
/******/ 	
/************************************************************************/

/******/ 	// module exports must be returned from runtime so entry inlining is disabled
/******/ 	// startup
/******/ 	// Load entry module and return exports
/******/ 	return __webpack_require__(0);
/******/ })()
;

dist/dll-manifest.json

{"name":"dll_84b3c692d890d26bb885","content":{"./example.js":{"id":1,"buildMeta":{"exportsType":"namespace"},"exports":["a","b","c"]}}}

Info

Unoptimized

asset dll.js 4.58 KiB [emitted] (name: dll)
chunk dll.js (dll) 211 bytes (javascript) 668 bytes (runtime) [entry] [rendered]
  > dll
  runtime modules 668 bytes 3 modules
  dependent modules 199 bytes [dependent] 2 modules
  dll dll 12 bytes [built] [code generated]
    [used exports unknown]
    dll entry
    used as library export
webpack 5.0.0-beta.32 compiled successfully

Production mode

asset dll.js 675 bytes [emitted] [minimized] (name: dll)
chunk (runtime: dll) dll.js (dll) 211 bytes (javascript) 668 bytes (runtime) [entry] [rendered]
  > dll
  runtime modules 668 bytes 3 modules
  dependent modules 199 bytes [dependent] 2 modules
  dll dll 12 bytes [built] [code generated]
    dll entry
    used as library export
webpack 5.0.0-beta.32 compiled successfully

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