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This very simple example shows usage of CommonJS.

The three files example.js, increment.js and math.js form a dependency chain. They use require(dependency) to declare dependencies.

You can see the output file that webpack creates by bundling them together in one file. Keep in mind that webpack adds comments to make reading this file easier. These comments are removed when minimizing the file.

You can also see the info messages webpack prints to console (for both normal and minimized build).

example.js

const inc = require('./increment').increment;
const a = 1;
inc(a); // 2

increment.js

const add = require('./math').add;
exports.increment = function(val) {
    return add(val, 1);
};

math.js

exports.add = function() {
    var sum = 0, i = 0, args = arguments, l = args.length;
    while (i < l) {
        sum += args[i++];
    }
    return sum;
};

dist/output.js

/******/ (() => { // webpackBootstrap
/******/ 	var __webpack_modules__ = ([
/* 0 */,
/* 1 */
/*!**********************!*\
  !*** ./increment.js ***!
  \**********************/
/*! exports [maybe provided (runtime-defined)] [no usage info] */
/*! runtime requirements: __webpack_require__, __webpack_exports__ */
/***/ ((__unused_webpack_module, exports, __webpack_require__) => {

const add = __webpack_require__(/*! ./math */ 2).add;
exports.increment = function(val) {
    return add(val, 1);
};


/***/ }),
/* 2 */
/*!*****************!*\
  !*** ./math.js ***!
  \*****************/
/*! exports [maybe provided (runtime-defined)] [no usage info] */
/*! runtime requirements: __webpack_exports__ */
/***/ ((__unused_webpack_module, exports) => {

exports.add = function() {
    var sum = 0, i = 0, args = arguments, l = args.length;
    while (i < l) {
        sum += args[i++];
    }
    return sum;
};

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

/* 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] = {
/******/ 			i: moduleId,
/******/ 			l: false,
/******/ 			exports: {}
/******/ 		};
/******/ 	
/******/ 		// Execute the module function
/******/ 		__webpack_modules__[moduleId](module, module.exports, __webpack_require__);
/******/ 	
/******/ 		// Flag the module as loaded
/******/ 		module.l = true;
/******/ 	
/******/ 		// Return the exports of the module
/******/ 		return module.exports;
/******/ 	}
/******/ 	
/************************************************************************/

!function() {
/*!********************!*\
  !*** ./example.js ***!
  \********************/
/*! exports [maybe provided (runtime-defined)] [no usage info] */
/*! runtime requirements: __webpack_require__ */
const inc = __webpack_require__(/*! ./increment */ 1).increment;
const a = 1;
inc(a); // 2

}();
/******/ })()
;

Info

Unoptimized

Hash: 0a1b2c3d4e5f6a7b8c9d
Version: webpack 5.0.0-beta.6
    Asset      Size
output.js  2.23 KiB  [emitted]  [name: main]
Entrypoint main = output.js
chunk output.js (main) 326 bytes [entry] [rendered]
    > ./example.js main
 ./example.js 72 bytes [built]
     [used exports unknown]
     entry ./example.js main
 ./increment.js 98 bytes [built]
     [used exports unknown]
     cjs require ./increment ./example.js 1:12-34
 ./math.js 156 bytes [built]
     [used exports unknown]
     cjs require ./math ./increment.js 1:12-29

Production mode

Hash: 0a1b2c3d4e5f6a7b8c9d
Version: webpack 5.0.0-beta.6
    Asset       Size
output.js  333 bytes  [emitted]  [name: main]
Entrypoint main = output.js
chunk output.js (main) 326 bytes [entry] [rendered]
    > ./example.js main
 ./example.js 72 bytes [built]
     [no exports used]
     entry ./example.js main
 ./increment.js 98 bytes [built]
     cjs require ./increment ./example.js 1:12-34
 ./math.js 156 bytes [built]
     cjs require ./math ./increment.js 1:12-29

4.3 KiB Raw Blame History