Supported data types in Firebase - Commands & Configuration

Introduction

Firebase stores data in a flexible way using different types. Knowing these types helps you save and read data correctly without errors.

When you want to save a user's name as text in your app database

When you need to store a number like age or score for a player

When you want to save a list of items like shopping list or tasks

When you need to store true or false values for settings

When you want to save a date and time for events or logs

Commands

This command creates a Firestore document for user1 with different data types: string, number, boolean, array, and timestamp.

Terminal

firebase firestore:documents:create users/user1 --data '{"name":"Alice","age":30,"isActive":true,"tags":["admin","user"],"lastLogin":{"seconds":1625097600,"nanoseconds":0}}'

Expected Output

Document users/user1 created successfully.

→

--data - Specifies the data to store in the document using JSON format

This command retrieves the document for user1 to verify the stored data types and values.

Terminal

firebase firestore:documents:get users/user1

Expected Output

Document data for users/user1:

{

  "name": "Alice",

  "age": 30,

  "isActive": true,

  "tags": ["admin", "user"],

  "lastLogin": {

    "seconds": 1625097600,

    "nanoseconds": 0

  }

}

Key Concept

If you remember nothing else from this pattern, remember: Firebase supports strings, numbers, booleans, arrays, maps, and timestamps as main data types to store your app data.

Common Mistakes

Trying to store a date as a plain string instead of a timestamp object

This causes problems when querying or sorting by date because Firebase treats it as text, not time.

Use Firebase timestamp objects with seconds and nanoseconds fields to store dates.

Saving complex objects without using maps, just as strings

You lose the ability to query or update nested fields properly.

Use maps (nested JSON objects) to store structured data.

Summary

Use strings for text like names and descriptions.

Use numbers for counts, ages, or scores.

Use booleans for true/false settings.

Use arrays to store lists of values.

Use timestamps to store dates and times correctly.