metro.config.js

const path = require('path');
const { getDefaultConfig } = require('expo/metro-config');
const pkg = require('../package.json');

const root = path.resolve(__dirname, '..');

// Dedupe the library's peer deps (react, react-native) to the example's copy,
// so Metro never loads a second react-native from the library root's own
// node_modules (the library dev-installs a different RN version).
const peers = Object.keys(pkg.peerDependencies || {});

function escapeRegExp(str) {
  return str.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
}

/**
 * Standalone Metro config (the example is NOT a yarn workspace). It watches the
 * library source at `../src` so edits hot-reload without a `bob build`, while
 * resolving react / react-native from the example's own node_modules.
 */
const config = getDefaultConfig(__dirname);

config.watchFolders = [root];

const blockedPeerPaths = peers.map(
  (name) =>
    new RegExp(`^${escapeRegExp(path.join(root, 'node_modules', name))}\\/.*$`)
);

// Merge with Expo's default blockList rather than replace it.
const existingBlockList = config.resolver.blockList;
config.resolver.blockList = existingBlockList
  ? [
      ...(Array.isArray(existingBlockList)
        ? existingBlockList
        : [existingBlockList]),
      ...blockedPeerPaths,
    ]
  : blockedPeerPaths;

config.resolver.extraNodeModules = peers.reduce((acc, name) => {
  acc[name] = path.join(__dirname, 'node_modules', name);
  return acc;
}, {});

module.exports = config;