Change frontmatter of old blog posts

setRedirect.js

const fs = require('fs');

fs.readdir('./', (err, files) => {
  if (err) {
    throw new Error(err);
  }

  const oldPosts = files.filter(file => /\.md$/.test(file));

  oldPosts.forEach(post => injectRedirectTo(post));
});

function injectRedirectTo(fileName) {
  const originalPath = fileName.match(/\d{4}-\d{2}-\d{2}-(.*)\.md$/)[1];
  const redirectTo = `https://emaren84.github.io/posts/${originalPath}`;
  const replaceText = `redirect_to:\n  - ${redirectTo}\ncategories:`;

  fs.readFile(fileName, 'utf8', (err, data) => {
    if (err) {
      throw new Error(err);
    }

    const result = data.replace(/categories\:/, replaceText);

    fs.writeFile(fileName, result, (err) => {
      if (err) {
        throw new Error(err);
      }
    });
  });
}