feat: adds metro-core, metro-plugin-rnc-cli, metro-plugin-rnef packages

Author: theGrep01

package.json

@@ -213,6 +213,7 @@
     "tailwindcss": "3.4.13",
     "terser-webpack-plugin": "^5.3.10",
     "ts-jest": "29.1.5",
+    "ts-node": "10.9.1",
     "tslib": "2.8.1",
     "tsup": "7.3.0",
     "typescript": "5.8.3",

packages/metro-core/.eslintrc.json

@@ -0,0 +1,41 @@
+{
+  "extends": ["../../.eslintrc.json"],
+  "ignorePatterns": [
+    "!**/*",
+    "**/*.d.ts",
+    "**/vite.config.*.timestamp*",
+    "**/vitest.config.*.timestamp*"
+  ],
+  "overrides": [
+    {
+      "files": ["*.ts", "*.tsx", "*.js", "*.jsx"],
+      "rules": {
+        "@typescript-eslint/no-explicit-any": "off",
+        "@typescript-eslint/ban-ts-comment": "warn",
+        "@typescript-eslint/no-var-requires": 0,
+        "@typescript-eslint/no-restricted-imports": [
+          "error",
+          {
+            "paths": [
+              {
+                "name": "webpack",
+                "message": "Please use require(normalizeWebpackPath('webpack')) instead.",
+                "allowTypeImports": true
+              }
+            ],
+            "patterns": [
+              {
+                "group": ["webpack/lib/*"],
+                "message": "Please use require(normalizeWebpackPath('webpack')) instead.",
+                "allowTypeImports": true
+              }
+            ]
+          }
+        ]
+      }
+    },
+    {
+      "files": ["*.js", "*.jsx"]
+    }
+  ]
+}

packages/metro-core/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2025 Callstack and Zephyr Cloud
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

packages/metro-core/README.md

@@ -0,0 +1,11 @@
+# metro
+
+This library was generated with [Nx](https://nx.dev).
+
+## Building
+
+Run `nx build metro` to build the library.
+
+## Running unit tests
+
+Run `nx test metro` to execute the unit tests via [Jest](https://jestjs.io).

packages/metro-core/babel-plugin/index.js

@@ -0,0 +1,115 @@
+// reuse `@babel/types` from `metro`
+const metroPath = require.resolve('metro');
+const babelTypesPath = require.resolve('@babel/types', { paths: [metroPath] });
+const t = require(babelTypesPath);
+
+const UNSUPPORTED_IMPORT_MESSAGE =
+  'The module path for import() must be a static string literal. Expressions or variables are not supported.';
+const WEBPACK_IGNORE_COMMENT = 'webpackIgnore: true';
+
+function isIgnoredWebpackImport(path) {
+  const [firstArg] = path.node.arguments;
+
+  const comments = [
+    ...(firstArg?.leadingComments || []),
+    ...(path.node?.leadingComments || []),
+    ...(path.node?.innerComments || []),
+  ];
+
+  return (
+    t.isImport(path.node.callee) &&
+    comments.some((comment) => comment.value.includes(WEBPACK_IGNORE_COMMENT))
+  );
+}
+
+function getRemotesRegExp(remotes) {
+  return new RegExp(`^(${Object.keys(remotes).join('|')})/`);
+}
+
+function getSharedRegExp(shared) {
+  return new RegExp(`^(${Object.keys(shared).join('|')})$`);
+}
+
+function isRemoteImport(path, options) {
+  return (
+    t.isImport(path.node.callee) &&
+    t.isStringLiteral(path.node.arguments[0]) &&
+    Object.keys(options.remotes).length > 0 &&
+    path.node.arguments[0].value.match(getRemotesRegExp(options.remotes))
+  );
+}
+
+function isSharedImport(path, options) {
+  return (
+    t.isImport(path.node.callee) &&
+    t.isStringLiteral(path.node.arguments[0]) &&
+    Object.keys(options.shared).length > 0 &&
+    path.node.arguments[0].value.match(getSharedRegExp(options.shared))
+  );
+}
+
+function createWrappedImport(importName, methodName) {
+  const importArg = t.stringLiteral(importName);
+
+  // require('mf:remote-module-registry')
+  const requireCall = t.callExpression(t.identifier('require'), [
+    t.stringLiteral('mf:remote-module-registry'),
+  ]);
+
+  // .loadAndGetRemote(importName) or .loadAndGetShared(importName)
+  const loadAndGetCall = t.callExpression(
+    t.memberExpression(requireCall, t.identifier(methodName)),
+    [importArg],
+  );
+
+  return loadAndGetCall;
+}
+
+function getWrappedRemoteImport(importName) {
+  return createWrappedImport(importName, 'loadAndGetRemote');
+}
+
+function getWrappedSharedImport(importName) {
+  return createWrappedImport(importName, 'loadAndGetShared');
+}
+
+function getRejectedPromise(errorMessage) {
+  return t.callExpression(
+    t.memberExpression(t.identifier('Promise'), t.identifier('reject')),
+    [t.newExpression(t.identifier('Error'), [t.stringLiteral(errorMessage)])],
+  );
+}
+
+function moduleFederationMetroBabelPlugin() {
+  return {
+    name: 'module-federation-metro-babel-plugin',
+    visitor: {
+      CallExpression(path, state) {
+        if (state.opts.blacklistedPaths.includes(state.filename)) {
+          return;
+        }
+
+        // Workaround to remove problematic import from `loadEsmEntry` in `@module-federation/runtime-core`
+        // That causes crashes in Metro bundler
+        if (isIgnoredWebpackImport(path)) {
+          path.replaceWith(getRejectedPromise(UNSUPPORTED_IMPORT_MESSAGE));
+          return;
+        }
+
+        if (isRemoteImport(path, state.opts)) {
+          const wrappedImport = getWrappedRemoteImport(
+            path.node.arguments[0].value,
+          );
+          path.replaceWith(wrappedImport);
+        } else if (isSharedImport(path, state.opts)) {
+          const wrappedImport = getWrappedSharedImport(
+            path.node.arguments[0].value,
+          );
+          path.replaceWith(wrappedImport);
+        }
+      },
+    },
+  };
+}
+
+module.exports = moduleFederationMetroBabelPlugin;

packages/metro-core/babel-plugin/patch-initialize-core.js

@@ -0,0 +1,61 @@
+// reuse `@babel/types` from `metro`
+const metroPath = require.resolve('metro');
+const babelTypesPath = require.resolve('@babel/types', { paths: [metroPath] });
+const t = require(babelTypesPath);
+
+/**
+ * Inject require('mf:init-host') right after 'use strict' directive
+ * in React Native's Initialize Core
+ */
+function injectInitHostRequire(path, state) {
+  // Only process once per file
+  if (state.hasInjected) return;
+
+  let insertIndex = 0;
+
+  // Find the position after 'use strict' directive
+  for (let i = 0; i < path.node.body.length; i++) {
+    const node = path.node.body[i];
+    if (
+      t.isExpressionStatement(node) &&
+      t.isStringLiteral(node.expression) &&
+      node.expression.value === 'use strict'
+    ) {
+      insertIndex = i + 1;
+      break;
+    }
+  }
+
+  // Create the require('mf:init-host') statement
+  const requireStatement = t.expressionStatement(
+    t.callExpression(t.identifier('require'), [
+      t.stringLiteral('mf:init-host'),
+    ]),
+  );
+
+  // Insert the require statement
+  path.node.body.splice(insertIndex, 0, requireStatement);
+  state.hasInjected = true;
+}
+
+function metroPatchInitializeCorePlugin() {
+  return {
+    name: 'module-federation-metro-patch-initialize-core',
+    visitor: {
+      Program: {
+        enter(_, state) {
+          state.hasInjected = false;
+          state.shouldTransform = state.file.opts.filename.includes(
+            'react-native/Libraries/Core/InitializeCore.js',
+          );
+        },
+        exit(path, state) {
+          if (!state.shouldTransform) return;
+          injectInitHostRequire(path, state);
+        },
+      },
+    },
+  };
+}
+
+module.exports = metroPatchInitializeCorePlugin;