deobfuscate-brs-files.ts

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

/*
some roku libraries obfuscate the code in their player.
We can deobfuscate a bunch of the code with these functions
*/
export function Chr(code) {
  var num = 0;
  if (code.substring(0, 2) === '&H') {
    var hexValue = code.substring(2, code.length);
    num = parseInt(hexValue, 16);
  } else {
    num = parseInt(code);
  }
  return String.fromCharCode(num);
}

export function deObfuscateFile(text) {
  var regex = /(?:Chr\()([a-z|A-Z|0-9|&]*)(?:\)\+*)/gim;
  var newText = text.replace(regex, (v0, v1) => {
    return Chr(v1);
  });
  return newText;
}


export function deObfuscate() {
  //this is a debug script it's
  const glob = require('glob-all');
  var outDir = `PATH/component-src-deobfuscated`;
  var srcDir = 'PATH/component-src';
  fs.removeSync(outDir);
  fs.mkdir(outDir);
  fs.copySync(srcDir, outDir);
  process.chdir(outDir);
  console.log(`processing out dir ${outDir}`);
  let files = glob.sync(['**/*.brs'], { cwd: outDir });

  for (const file of files) {
    var fullPath = path.resolve(file);
    console.log('found file ' + fullPath);
    let text = fs.readFileSync(fullPath, 'utf8');
    text = deObfuscateFile(text);
    fs.writeFileSync(fullPath, text, 'utf8');
  }
  console.log(`files are in ${outDir}`);
}