react-native-start-with-link.js

/**
 * Original gist by GingerBear: https://gist.github.com/GingerBear/485f922a1e403739dc56d279925b216d
 * I've removed runBundlerWithConfig
 * - check symlink in depencency and devDepency
 * - if found, generate rn-cli-config.js
 * - react-native start with rn-cli-config
 */

const packageJson = require('./package.json');
const fs = require('fs');
const exec = require('child_process').execSync;
const RN_CLI_CONFIG_NAME = `rn-cli.config.js`;

main();

function main() {
    const deps = Object.keys(
        Object.assign({}, packageJson.dependencies, packageJson.devDependencies)
    );

    const symlinkPathes = getSymlinkPathes(deps);
    generateRnCliConfig(symlinkPathes, RN_CLI_CONFIG_NAME);
}

function getSymlinkPathes(deps) {
    const depLinks = [];
    const depPathes = [];
    deps.forEach(dep => {
        const stat = fs.lstatSync('node_modules/' + dep);
        if (stat.isSymbolicLink()) {
            depLinks.push(dep);
            depPathes.push(fs.realpathSync('node_modules/' + dep));
        }
    });

    console.log('Starting react native with symlink modules:');
    console.log(
        depLinks.map((link, i) => '   ' + link + ' -> ' + depPathes[i]).join('\n')
    );

    return depPathes;
}

function generateRnCliConfig(symlinkPathes, configName) {
    const fileBody =
`
var path = require('path');
var blacklist;
try {
  blacklist = require('metro-bundler/src/blacklist');
} catch(e) {
  blacklist = require('metro/src/blacklist');
}
var config = {
  extraNodeModules: {
    'react-native': path.resolve(__dirname, 'node_modules/react-native')
  },
  getBlacklistRE() {
    return blacklist([
      ${symlinkPathes.map(
        path =>
            `/${path.replace(
                /\//g,
                '[/\\\\]'
            )}[/\\\\]node_modules[/\\\\]react-native[/\\\\].*/`
    )}
    ]);
  },
  getProjectRoots() {
    return [
      // Keep your project directory.
      path.resolve(__dirname),
      // Include your forked package as a new root.
      ${symlinkPathes.map(path => `path.resolve('${path}')`)}
    ];
  }
};

module.exports = config;
`;

    fs.writeFileSync(configName, fileBody);
}