react-native/local-cli/link/ios/hasLibraryImported.js

/**
 * Given an array of libraries already imported and packageName that will be
 * added, returns true or false depending on whether the library is already linked
 * or not
 */
module.exports = function hasLibraryImported(libraries, packageName) {
  return libraries.children
    .filter(library => library.comment === packageName)
    .length > 0;
};