Convert Firebase Database JSON to Firestore Collections

FirebaseToFirestore.js

var db = firebase.firestore();
var content = require("./sourceData.json");

content &&
  Object.keys(content).forEach(contentKey => {
    const nestedContent = content[contentKey];
    if (typeof nestedContent === "object") {
      Object.keys(nestedContent).forEach(docTitle => {
        firebase
          .firestore()
          .collection(contentKey)
          .doc(docTitle)
          .set(nestedContent[docTitle]);
      });
    }
  });