code: function buildFile() {
      var reader = readline.createInterface({
          input: fs.createReadStream(path.resolve("./src/assets/template.html"))
      });
      
      var lines = [];
      reader.on("line", line => lines.push(line));
  
      return new Promise(resolve => {
          reader.on("close", () => resolve(buildJsFileContents(lines)));
      });
  }
docs: Build a promise which will generate css -> js file contents