Deduplicate rules in .gitignore

deduplicate-gitignore.mjs

#!/usr/bin/env zx

const gitignoreFile = argv._[0];

const content = await fs.readFile(gitignoreFile, { encoding: "utf-8" });

const rulesSet = new Set();
const lines = content.split(`\n`);

const newLines = lines.filter((l) => {
  const isComment = !l.trim().startsWith("#");
  if (!isComment) {
    if (!l) {
      if (!rulesSet.has(l)) {
        rulesSet.add(l);
      } else {
        return false;
      }
    }
  }

  return true;
});

const newContent = newLines.join("\n");
console.log(newContent);