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]); }); } });