chaos-string-test.js

export const chaosTestStrings = (): void => {
  const textNodes = getAllTextNodes(document.body);

  for (const node of textNodes) {
    const textNodeLength = node.textContent ? node.textContent.length : 0;
    if (node.textContent === null) {
      return;
    }
    if (node.parentElement instanceof Element) {
      if (node.parentElement.dataset.originalText === undefined) {
        node.parentElement.dataset.originalText = node.textContent;
        node.textContent = generateRandomString(textNodeLength * 3);
      } else {
        node.textContent = node.parentElement.dataset.originalText;
        node.parentElement.removeAttribute('data-original-text');
      }
    }
  }
};

const PARENT_TAGS_TO_EXCLUDE = new Set(['STYLE', 'SCRIPT', 'TITLE']);
const RANDOM_CHARACTERS =
  'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789 ';

function* walkDOMTree(
  root: Node,
  whatToShow: number = NodeFilter.SHOW_ALL,
  {
    inspect,
    collect,
    callback,
  }: {
    inspect?: (node: Node) => boolean;
    collect?: (node: Node) => boolean;
    callback?: (node: Node) => void;
  } = {},
): Generator<Node, void> {
  const walker = document.createTreeWalker(root, whatToShow, {
    acceptNode(node) {
      if (inspect && !inspect(node)) {
        return NodeFilter.FILTER_REJECT;
      }
      if (collect && !collect(node)) {
        return NodeFilter.FILTER_SKIP;
      }
      return NodeFilter.FILTER_ACCEPT;
    },
  });

  let n;
  while ((n = walker.nextNode())) {
    callback?.(n);
    yield n;
  }
}

function* getAllTextNodes(el: Node): Generator<Node, void> {
  yield* walkDOMTree(el, NodeFilter.SHOW_TEXT, {
    inspect: (textNode: Node) =>
      !PARENT_TAGS_TO_EXCLUDE.has(textNode.parentElement?.nodeName || ''),
  });
}

function generateRandomString(length: number): string {
  return Array.from(
    { length },
    () =>
      RANDOM_CHARACTERS[Math.floor(Math.random() * RANDOM_CHARACTERS.length)],
  ).join('');
}