Rules import resolver Medium Article

generate_rules.js

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

// TODO: Add your exact paths
const srcFile = path.join(__dirname, "rules", "index.rules");
const destFile = path.join(__dirname, "firestore.rules");

fs.writeFileSync(destFile, resolveImports(srcFile));

function resolveImports(filePath) {
  const rulesFile = fs.readFileSync(filePath).toString();
  
  // Every second element in the array will have the file name to the imported file
  const fileElements = rulesFile.split(/include "([A-Za-z0-9\/.]+\.rules)";/);
  
  // Resolve imports
  let resolvedRulesFile = "";
  let isImport = false;
  
  for (const elem of fileElements) {
    if (isImport) {
      const importPath = path.join(filePath, "..", elem);
      resolvedRulesFile += resolveImports(importPath);
    } else {
      resolvedRulesFile += elem;
    }
    isImport = !isImport;
  }
  return resolvedRulesFile;
}