Parse the Book of Blaseball from the site's minified JavaScript

package.json

{
  "name": "blaseball-book-scraper",
  "version": "1.0.0",
  "description": "",
  "main": "parse_blaseball_book.js",
  "author": "",
  "license": "ISC",
  "dependencies": {
    "acorn": "^7.4.0",
    "acorn-walk": "^7.2.0",
    "bent": "^7.3.9",
    "cheerio": "^1.0.0-rc.3"
  }
}

parse_blaseball_book.js

const url = require('url');
const bent = require('bent');
const cheerio = require('cheerio');
const acorn = require('acorn');
const walk = require('acorn-walk');

const getString = bent('string');

async function parseBookFromJavaScript() {
  const html = await getString('https://blaseball.com');
  const $ = cheerio.load(html);

  const scriptTags = $('script[src^="/static/js/main\."]');
  if (scriptTags.length === 0) {
    throw new Error('Could not find the main JS file.')
  }
  if (scriptTags.length > 1) {
    throw new Error('More than one main JS files found.')
  }

  const src = scriptTags.attr('src');
  const jsUrl = url.resolve('https://blaseball.com', src);
  const js = await getString(jsUrl);

  const ast = acorn.parse(js);

  let bookFunctionNode = null;
  walk.ancestor(ast, {
    Literal(node, ancestors) {
      if (node.value !== 'The Book of Blaseball' || bookFunctionNode !== null || ancestors.length <= 1) {
        return;
      }

      // start at the 2nd-to-last ancestor since the last ancestor is the current node
      for (let i = ancestors.length - 2; i >= 0; i--) {
        if (ancestors[i].type === 'FunctionDeclaration') {
          bookFunctionNode = ancestors[i];
          break;
        }
      }
    }
  });

  if (bookFunctionNode === null) {
    throw new Error('Could not find the FunctionDeclaration node for rendering the Book in the AST.')
  }

  let text = '';

  walk.recursive(bookFunctionNode, null, {
    CallExpression(node, st, c) {
      const isCreateElement = (
        node.callee.type === 'MemberExpression' &&
        node.callee.property.type === 'Identifier' &&
        node.callee.property.name === 'createElement'
      );
      if (!isCreateElement) {
        return;
      }

      c(node.callee, st, 'Expression');

      if (!node.arguments) {
        return;
      }

      for (let i = 0; i < node.arguments.length; i++) {
        if (i === 0 && node.arguments[0].type === 'Literal') { // HTML tag
          if (node.arguments[0].value === 'div' && text !== '') {
            text += '\n';
          }
          continue;
        }

        const isLiteral = (
          node.arguments[i].type === 'Literal' &&
          node.arguments[i].value !== null
        );
        const hasStrProperty = (
          node.arguments[i].type === 'ObjectExpression' &&
          node.arguments[i].properties.length === 1 &&
          node.arguments[i].properties[0].key.name === 'str'
        );
        const hasClassNameProperty = (
          node.arguments[i].type === 'ObjectExpression' &&
          node.arguments[i].properties.length === 1 &&
          node.arguments[i].properties[0].key.name === 'className'
        );

        if (isLiteral) {
          text += node.arguments[i].value;
        } else if (hasStrProperty) {
          text += node.arguments[i].properties[0].value.value;
        } else if (hasClassNameProperty) {
          const classNames = node.arguments[i].properties[0].value.value.split(' ');
          if (classNames.includes('TheBook-Bullet')) {
            text += '\n'
          } else if (classNames.includes('TheBook-SubBullet')) {
            text += '  '
          }
        }

        c(node.arguments[i], st, 'Expression');
      }
    }
  });

  return text;
}

(async () => {
  try {
    const text = await parseBookFromJavaScript();
    console.log(text);
  } catch (e) {
    console.error(e);
  }
})();