async function processJSWithSrc()

in src/js/background.js [234:292]
51 lines of code
6 McCabe index (conditional complexity)

async function processJSWithSrc(message, manifest, tabId) {
  try {
    const sourceResponse = await fetch(message.src, { method: 'GET' });
    let sourceText = await sourceResponse.text();
    if (sourceText.indexOf('if (self.CavalryLogger) {') === 0) {
      sourceText = sourceText.slice(82).trim();
    }
    // we want to slice out the source URL from the source
    const sourceURLIndex = sourceText.indexOf('//# sourceURL');
    if (sourceURLIndex >= 0) {
      // doing minus 1 because there's usually either a space or new line
      sourceText = sourceText.slice(0, sourceURLIndex - 1);
    }
    // if ([ORIGIN_TYPE.FACEBOOK].includes(message.origin)) {
    //   sourceText = unescape(sourceText);
    // }
    // strip i18n delimiters
    // eslint-disable-next-line no-useless-escape
    const i18nRegexp = /\/\*FBT_CALL\*\/.*?\/\*FBT_CALL\*\//g;
    const i18nStripped = sourceText.replace(i18nRegexp, '');
    // split package up if necessary
    const packages = i18nStripped.split('/*FB_PKG_DELIM*/\n');
    const encoder = new TextEncoder();
    for (let i = 0; i < packages.length; i++) {
      const encodedPackage = encoder.encode(packages[i]);
      const packageHashBuffer = await crypto.subtle.digest(
        'SHA-256',
        encodedPackage
      );
      const packageHash = Array.from(new Uint8Array(packageHashBuffer))
        .map(b => b.toString(16).padStart(2, '0'))
        .join('');
      console.log(
        'manifest is ',
        manifest.leaves.length,
        manifest.leaves.includes(packageHash),
        packageHash
      );
      if (!manifest.leaves.includes(packageHash)) {
        return false;
      }
    }
    return true; // YAY!
  } catch (error) {
    console.log('error occurred!', error);
    addDebugLog(
      tabId,
      'Error: Processing JS with SRC ' +
        message.origin +
        ', ' +
        message.version +
        ' problematic JS is ' +
        message.src +
        'error is ' +
        JSON.stringify(error).substring(0, 500)
    );
    return false;
  }
}