@bernhste/obfuscator-io-metro-plugin/lib/utils.js

A metro plugin to use javascript-obfuscator library with react-native

const readline = require('readline');
const {Command} = require('commander');
const {Readable} = require('stream');
const {
  EXTS,
  END_ANNOTATION,
  BEG_ANNOTATION,
  BUNDLE_OUTPUT_CLI_ARG,
  BUNDLE_SOURCEMAP_OUTPUT_CLI_ARG,
  BUNDLE_DEV_CLI_ARG,
  BUNDLE_CMD
} = require('./constants');

/**
 * Only 'bundle' command triggers obfuscation.
 * Development bundles will be ignored (--dev true). Use JSO_METRO_DEV to override this behaviour.
 * @returns {string} skip reason. If falsy value dont skip obfuscation
 */
function skipObfuscation({ runInDev }) {
  let isBundleCmd = false;
  const command = new Command();
  command
    .command(BUNDLE_CMD)
    .allowUnknownOption()
    .action(() => (isBundleCmd = true));
  command.option(`${BUNDLE_DEV_CLI_ARG} <boolean>`).parse(process.argv);
  if (!isBundleCmd) {
    return 'Not a *bundle* command';
  }
  if (command.dev === 'true') {
    return (
      !runInDev &&
      'Development mode. Override with JSO_METRO_DEV=true environment variable'
    );
  }
  return null;
}

/**
 * Get bundle path based CLI arguments
 * @returns {{bundlePath: string, bundleSourceMapPath: string}}
 * @throws {Error} when bundle output was not found
 */
function getBundlePath() {
  const command = new Command();
  command
    .option(`${BUNDLE_OUTPUT_CLI_ARG} <string>`)
    .option(`${BUNDLE_SOURCEMAP_OUTPUT_CLI_ARG} <string>`)
    .parse(process.argv);
  if (command.bundleOutput) {
    return {
      bundlePath: command.bundleOutput,
      bundleSourceMapPath: command.sourcemapOutput
    };
  }
  console.error('Bundle output path not found.');
  return process.exit(-1);
}

/**
 * Strip all  tags from code
 * @param {string} code
 * @returns {string}
 */
function stripTags(code) {
  return code.replace(new RegExp(BEG_ANNOTATION, 'g'), '')
    .replace(new RegExp(END_ANNOTATION, 'g'), '')
}

/**
 * When next character is a new line (\n or \r\n),
 * we should increment startIndex to avoid user code starting with a new line.
 * @param {string} startIndex
 * @param {string} code
 * @returns {number}
 * @example
 *    __d(function(g,r,i,a,m,e,d){(detect new line here and start below)
 *      // user code
 *      ...
 *    }
 */
function shiftStartIndexOnNewLine(startIndex, code) {
  switch (code[startIndex + 1]) {
    case '\r':
      startIndex++;
      return shiftStartIndexOnNewLine(startIndex, code);
    case '\n':
      startIndex++;
      break;
  }
  return startIndex;
}

/**
 * Wrap user code with  TAGS {BEG_ANNOTATION and END_ANNOTATION}
 * @param {{code: string}} data
 */
function wrapCodeWithTags(data) {
  let startIndex = data.code.indexOf('{');
  const endIndex = data.code.lastIndexOf('}');
  startIndex = shiftStartIndexOnNewLine(startIndex, data.code);
  const init = data.code.substring(0, startIndex + 1);
  const clientCode = data.code.substring(startIndex + 1, endIndex);
  const end = data.code.substr(endIndex, data.code.length);
  data.code = init + BEG_ANNOTATION + clientCode + END_ANNOTATION + end;
}

/**
 * @param {string} path
 * @param {string} projectRoot
 * @returns {string} undefined if path is empty or invalid
 *
 * @example
 *    <project_root>/react-native0.59-grocery-list/App/index.js -> App/index.js
 *    <project_root>/react-native0.59-grocery-list/App/index.ts -> App/index.js
 */
function buildNormalizePath(path, projectRoot) {
  if (typeof path !== 'string' || path.trim().length === 0) {
    return;
  }
  const relativePath = path.replace(projectRoot, '');
  return relativePath.replace(EXTS, '.js').substring(1 /* remove '/' */);
}

module.exports = {
  skipObfuscation,
  getBundlePath,
  stripTags,
  wrapCodeWithTags,
  buildNormalizePath
}