TitleCase Jekyll Titles With Node

titlecase_jekyll_titles.js

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

const directoryPath = path.join(__dirname, '_posts');
// Loop through the folder's files
fs.readdir(directoryPath, (err, files) => {
  if (err) {
    return console.log('Unable to scan directory: ' + err);
  }
  // Loop through all files
  files.forEach((filename) => {
    const file = `${directoryPath}/${filename}`;
    fs.readFile(file, 'utf-8', (err, data) => {
      // Split the content with `---`. The second key will be what we want
      const frontMatter = data.split('---');
      if (frontMatter) {
        // Parse the frontMatter and find the title
        const [originalTitle, uselessKey, title] = frontMatter[1].match(
          /(title:\s*)(.+)/im
        );
        // These words should not be capitalised
        const smallWords = /^(a|an|and|as|at|but|by|en|for|if|in|nor|of|on|or|per|the|to|v.?|vs.?|via)$/i;
        // Split the title by spaces
        let newTitle = title
          .split(' ')
          // Loop through all the items
          .map((item, index, array) => {
            if (
              // Does it belong to the smallwords
              item.search(smallWords) > -1 &&
              // and it's not first or last word
              index !== 0 &&
              index !== array.length - 1
            ) {
              // This needs to be lowercase
              return item.toLowerCase();
            } else {
              // Everything else should be capitalised
              return item.replace(/^['A-Za-z']/, (item) => item.toUpperCase());
            }
          })
          .join(' ');

        // Replace the old title with the new one in the original content
        data = data.replace(originalTitle, `title: ${newTitle}`);
        fs.writeFile(file, data, (err, result) => {
          if (err) console.log('something went wrong with ' + file);
          console.log('Yay!');
        });
      }
    });
  });
});