Viewing github.com/facebook/react/packages/react-server-dom-webpack/src/__tests__/utils/WebpackMock.js

```
/**
```

 * Copyright (c) Meta Platforms, Inc. and affiliates.

```
 *
```

 * This source code is licensed under the MIT license found in the

 * LICENSE file in the root directory of this source tree.

```
 */
```
```
'use strict';
```
```
const url = require('url');
```
```
const Module = require('module');
```
```
let webpackModuleIdx = 0;
```
```
const webpackServerModules = {};
```
```
const webpackClientModules = {};
```
```
const webpackErroredModules = {};
```
```
const webpackServerMap = {};
```
```
const webpackClientMap = {};
```

global.__webpack_require__ = function (id) {

```
  if (webpackErroredModules[id]) {
```
```
    throw webpackErroredModules[id];
```
```
  }
```

  return webpackClientModules[id] || webpackServerModules[id];

```
};
```

const previousCompile = Module.prototype._compile;

const register = require('react-server-dom-webpack/node-register');

```
// Register node compile
```
```
register();
```

const nodeCompile = Module.prototype._compile;

```
if (previousCompile === nodeCompile) {
```
```
  throw new Error(
```

    'Expected the Node loader to register the _compile extension',

```
  );
```
```
}
```

Module.prototype._compile = previousCompile;

```
exports.webpackMap = webpackClientMap;
```

exports.webpackModules = webpackClientModules;

exports.webpackServerMap = webpackServerMap;

```
exports.moduleLoading = {
```
```
  prefix: '/',
```
```
};
```

exports.clientModuleError = function clientModuleError(moduleError) {

```
  const idx = '' + webpackModuleIdx++;
```

  webpackErroredModules[idx] = moduleError;

  const path = url.pathToFileURL(idx).href;

```
  webpackClientMap[path] = {
```
```
    id: idx,
```
```
    chunks: [],
```
```
    name: '*',
```
```
  };
```
```
  const mod = {exports: {}};
```

  nodeCompile.call(mod, '"use client"', idx);

```
  return mod.exports;
```
```
};
```

exports.clientExports = function clientExports(

```
  moduleExports,
```
```
  chunkId,
```
```
  chunkFilename,
```
```
) {
```
```
  const chunks = [];
```
```
  if (chunkId) {
```

    chunks.push(chunkId, chunkFilename);

```
  }
```
```
  const idx = '' + webpackModuleIdx++;
```

  webpackClientModules[idx] = moduleExports;

  const path = url.pathToFileURL(idx).href;

```
  webpackClientMap[path] = {
```
```
    id: idx,
```
```
    chunks,
```
```
    name: '*',
```
```
  };
```

  // We only add this if this test is testing ESM compat.

```
  if ('__esModule' in moduleExports) {
```
```
    webpackClientMap[path + '#'] = {
```
```
      id: idx,
```
```
      chunks,
```
```
      name: '',
```
```
    };
```
```
  }
```

  if (typeof moduleExports.then === 'function') {

```
    moduleExports.then(
```
```
      asyncModuleExports => {
```

        for (const name in asyncModuleExports) {

          webpackClientMap[path + '#' + name] = {

```
            id: idx,
```
```
            chunks,
```
```
            name: name,
```
```
          };
```
```
        }
```
```
      },
```
```
      () => {},
```
```
    );
```
```
  }
```
```
  if ('split' in moduleExports) {
```

    // If we're testing module splitting, we encode this name in a separate module id.

    const splitIdx = '' + webpackModuleIdx++;

```
    webpackClientModules[splitIdx] = {
```
```
      s: moduleExports.split,
```
```
    };
```

    webpackClientMap[path + '#split'] = {

```
      id: splitIdx,
```
```
      chunks,
```
```
      name: 's',
```
```
    };
```
```
  }
```
```
  const mod = {exports: {}};
```

  nodeCompile.call(mod, '"use client"', idx);

```
  return mod.exports;
```
```
};
```

// This tests server to server references. There's another case of client to server references.

exports.serverExports = function serverExports(moduleExports) {

```
  const idx = '' + webpackModuleIdx++;
```

  webpackServerModules[idx] = moduleExports;

  const path = url.pathToFileURL(idx).href;

```
  webpackServerMap[path] = {
```
```
    id: idx,
```
```
    chunks: [],
```
```
    name: '*',
```
```
  };
```

  // We only add this if this test is testing ESM compat.

```
  if ('__esModule' in moduleExports) {
```
```
    webpackServerMap[path + '#'] = {
```
```
      id: idx,
```
```
      chunks: [],
```
```
      name: '',
```
```
    };
```
```
  }
```
```
  if ('split' in moduleExports) {
```

    // If we're testing module splitting, we encode this name in a separate module id.

    const splitIdx = '' + webpackModuleIdx++;

```
    webpackServerModules[splitIdx] = {
```
```
      s: moduleExports.split,
```
```
    };
```

    webpackServerMap[path + '#split'] = {

```
      id: splitIdx,
```
```
      chunks: [],
```
```
      name: 's',
```
```
    };
```
```
  }
```

  const mod = {exports: moduleExports};

  nodeCompile.call(mod, '"use server"', idx);

```
  return mod.exports;
```
```
};
```

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