Firestore security rules validation example

client.js

import * as firebase from "firebase/app";
import 'firebase/firestore';
import config from './config';

firebase.initializeApp(config);

const data = {
  string: 'foo',
  integer: 23,
  boolean: false,
  timestamp: firebase.firestore.Timestamp.fromDate(new Date())
};

const doc = firebase.firestore().doc('path/to/doc');

doc.set(data).then(() => console.log('success')).catch(e => console.error(e));

rules.js

match /path/to/data {
  allow read: if true;
  allow write: if 
      // must have exactly 4 fields with keys 'string', 'integer', 'boolean', and 'timestamp'
      request.resource.data.size() == 4 && request.resource.data.keys().hasAll(['string', 'integer', 'boolean', 'timestamp']) && 
      // string field must be less than 10 characters
      request.resource.data.string is string && request.resource.data.string.size() < 10 &&
      // integer field must be between 0 and 1000
      request.resource.data.integer is int && request.resource.data.integer > -1 && request.resource.data.integer < 1001 && 
      // boolean field must be a boolean
      request.resource.data.boolean is bool && 
      // timestamp must by a timestamp
      request.resource.data.timestamp is timestamp
}