examples_postinstall.js

#!/usr/bin/env node

  /*
   * Using libraries within examples and linking them within packages.json like:
   * "react-native-library-name": "file:../"
   * will cause problems with the metro bundler if the example will run via
   * `react-native run-[ios|android]`. This will result in an error as the metro
   * bundler will find multiple versions for the same module while resolving it.
   * The reason for that is that if the library is installed it also copies in the
   * example folder itself as well as the node_modules folder of the library
   * although their are defined in .npmignore and should be ignored in theory.
   *
   * This postinstall script removes the node_modules folder as well as all
   * entries from the libraries .npmignore file within the examples node_modules
   * folder after the library was installed. This should resolve the metro
   * bundler issue mentioned above.
   *
   * It is expected this scripts lives in the libraries root folder within a
   * scripts folder. As first parameter the relative path to the libraries
   * folder within the example's node_modules folder may be provided.
   * This script will determine the path from this project's package.json file
   * if no such relative path is provided.
   * An example's package.json entry could look like:
   * "postinstall": "node ../scripts/examples_postinstall.js node_modules/react-native-library-name/"
   */

  'use strict';

  const fs = require('fs');
  const path = require('path');

  /// Delete all files and directories for the given path
  const removeFileDirectoryRecursively = fileDirPath => {
    // Remove file
    if (!fs.lstatSync(fileDirPath).isDirectory()) {
      fs.unlinkSync(fileDirPath);
      return;
    }

    // Go down the directory an remove each file / directory recursively
    fs.readdirSync(fileDirPath).forEach(entry => {
      const entryPath = path.join(fileDirPath, entry);
      removeFileDirectoryRecursively(entryPath);
    });
    fs.rmdirSync(fileDirPath);
  };

  /// Remove example/node_modules/react-native-library-name/node_modules directory
  const removeLibraryNodeModulesPath = (libraryNodeModulesPath) => {
    const nodeModulesPath = path.resolve(libraryNodeModulesPath, 'node_modules')

    if (!fs.existsSync(nodeModulesPath)) {
      console.log(`No node_modules path found at ${nodeModulesPath}. Skipping delete.`)
      return;
    }

    console.log(`Deleting: ${nodeModulesPath}`)
    try {
      removeFileDirectoryRecursively(nodeModulesPath);
      console.log(`Successfully deleted: ${nodeModulesPath}`)
    } catch (err) {
      console.log(`Error deleting ${nodeModulesPath}: ${err.message}`);
    }
  };

  /// Remove all entries from the .npmignore within  example/node_modules/react-native-library-name/
  const removeLibraryNpmIgnorePaths = (npmIgnorePath, libraryNodeModulesPath) => {
    if (!fs.existsSync(npmIgnorePath)) {
      console.log(`No .npmignore path found at ${npmIgnorePath}. Skipping deleting content.`);
      return;
    }

    fs.readFileSync(npmIgnorePath, 'utf8').split(/\r?\n/).forEach(entry => {
      if (entry.length === 0) {
        return
      }

      const npmIgnoreLibraryNodeModulesEntryPath = path.resolve(libraryNodeModulesPath, entry);
      if (!fs.existsSync(npmIgnoreLibraryNodeModulesEntryPath)) {
        return;
      }

      console.log(`Deleting: ${npmIgnoreLibraryNodeModulesEntryPath}`)
      try {
        removeFileDirectoryRecursively(npmIgnoreLibraryNodeModulesEntryPath);
        console.log(`Successfully deleted: ${npmIgnoreLibraryNodeModulesEntryPath}`)
      } catch (err) {
        console.log(`Error deleting ${npmIgnoreLibraryNodeModulesEntryPath}: ${err.message}`);
      }
    });
  };

  // Main start sweeping process
  (() => {
    // Read out dir of example project
    const exampleDir = process.cwd();

    console.log(`Starting postinstall cleanup for ${exampleDir}`);

    // Resolve the React Native library's path within the example's node_modules directory
    const libraryNodeModulesPath = process.argv.length > 2
      ? path.resolve(exampleDir, process.argv[2])
      : path.resolve(exampleDir, 'node_modules', require('../package.json').name);

    console.log(`Removing unwanted artifacts for ${libraryNodeModulesPath}`);

    removeLibraryNodeModulesPath(libraryNodeModulesPath);

    const npmIgnorePath = path.resolve(__dirname, '../.npmignore');
    removeLibraryNpmIgnorePaths(npmIgnorePath, libraryNodeModulesPath);
  })();