JavaScript client installation in Supabase - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the first step to install the Supabase JavaScript client in a project?

The first step is to run npm install @supabase/supabase-js in your project directory to add the Supabase client library.

beginner

How do you import the Supabase client in your JavaScript code after installation?

Use <code>import { createClient } from '@supabase/supabase-js'</code> to import the function that creates the Supabase client.

beginner

What information do you need to create a Supabase client instance?

You need your Supabase project URL and the public API key (anon key) to create the client with createClient(supabaseUrl, supabaseKey).

intermediate

Why is it important to keep your Supabase API key secure?

Because the API key allows access to your database and services. Sharing it publicly can lead to unauthorized access.

intermediate

Can you use the Supabase JavaScript client in both frontend and backend environments?

Yes, the Supabase client works in browsers and Node.js environments, making it flexible for frontend and backend use.

Which command installs the Supabase JavaScript client?

A npm install @supabase/supabase-js

B npm install supabase-client

C npm install supabase-js-client

D npm install supabase

The correct package name is '@supabase/supabase-js'.

What function do you use to create a Supabase client instance?

A createSupabase()

B initClient()

C createClient()

D supabaseClient()

The function to create the client is called createClient.

Which two pieces of information are required to initialize the Supabase client?

A Username and password

B Project URL and API key

C Database name and port

D API key and secret key

You need the project URL and the public API key (anon key) to initialize the client.

Where can you use the Supabase JavaScript client?

A Only in backend Node.js

B Only in frontend browsers

C Only in mobile apps

D Both frontend and backend environments

The client works in both frontend browsers and backend Node.js environments.

Why should you avoid exposing your Supabase API key publicly?

A It can cause unauthorized access

B It slows down your app

C It increases your billing

D It disables your database

Exposing the API key can allow others to access your database without permission.

Explain the steps to install and set up the Supabase JavaScript client in a new project.

Think about commands, imports, and configuration.

Describe why keeping your Supabase API key secure is important and how it relates to your app's safety.

Consider what could happen if someone else uses your key.

Practice

1. What is the correct command to install the Supabase JavaScript client using npm?

easy

A. npm install @supabase/supabase-js

B. npm install supabase-js

C. npm install supabase-client

D. npm install @supabase/client-js

Solution

1. Step 1: Identify the official package name

   The official Supabase JavaScript client package is named '@supabase/supabase-js'.

2. Step 2: Use npm install with the correct package

   The correct command is 'npm install @supabase/supabase-js' to install the client.

3. Final Answer:

   npm install @supabase/supabase-js -> Option A

4. Quick Check:

   Correct package name = npm install @supabase/supabase-js [OK]

Hint: Remember the package starts with '@supabase/' [OK]

Common Mistakes:

• Using incomplete package names
• Omitting the '@supabase/' prefix
• Confusing with other similar package names

2. Which of the following is the correct way to import the Supabase client in a JavaScript file after installation?

easy

A. const supabase = require('supabase-js');

B. import { createClient } from '@supabase/supabase-js';

C. import supabase from '@supabase/client';

D. const supabase = require('@supabase/supabase-js');

Solution

1. Step 1: Use ES module import syntax

   The Supabase client uses named export 'createClient' from '@supabase/supabase-js'.

2. Step 2: Confirm correct import statement

   The correct import is 'import { createClient } from '@supabase/supabase-js';'.

3. Final Answer:

   import { createClient } from '@supabase/supabase-js'; -> Option B

4. Quick Check:

   Use named import 'createClient' from '@supabase/supabase-js' [OK]

Hint: Use named import with curly braces for createClient [OK]

Common Mistakes:

• Using default import instead of named import
• Using wrong package name in import
• Mixing require and import syntax

3. Given the following code snippet, what will be the output of console.log(supabaseUrl)?

import { createClient } from '@supabase/supabase-js';
const supabaseUrl = 'https://xyzcompany.supabase.co';
const supabaseKey = 'public-anonymous-key';
const supabase = createClient(supabaseUrl, supabaseKey);
console.log(supabaseUrl);

medium

A. https://xyzcompany.supabase.co

B. undefined

C. An error because supabaseUrl is not defined

D. 'public-anonymous-key'

Solution

1. Step 1: Identify the variable logged

   The code logs 'supabaseUrl', which is defined as a string URL.

2. Step 2: Confirm the value of supabaseUrl

   It is set to 'https://xyzcompany.supabase.co', so logging it prints this string.

3. Final Answer:

   https://xyzcompany.supabase.co -> Option A

4. Quick Check:

   Variable supabaseUrl = 'https://xyzcompany.supabase.co' [OK]

Hint: Check which variable is logged exactly [OK]

Common Mistakes:

• Confusing supabaseUrl with supabaseKey
• Assuming logging supabase object instead
• Thinking variable is undefined

4. What is wrong with this code snippet for creating a Supabase client?

import { createClient } from '@supabase/supabase-js';
const supabaseUrl = 'https://xyzcompany.supabase.co';
const supabaseKey = 'public-anonymous-key';
const supabase = createClient(supabaseKey, supabaseUrl);

medium

A. The supabaseUrl is missing the protocol

B. The import statement is incorrect

C. The supabaseKey should be an environment variable

D. The arguments to createClient are reversed; URL should be first

Solution

1. Step 1: Check the order of arguments in createClient

   The function expects the URL first, then the key.

2. Step 2: Identify the mistake in argument order

   The code passes the key first and URL second, which is incorrect.

3. Final Answer:

   The arguments to createClient are reversed; URL should be first -> Option D

4. Quick Check:

   createClient(url, key) order matters [OK]

Hint: Remember: URL first, key second in createClient() [OK]

Common Mistakes:

• Swapping URL and key arguments
• Ignoring import correctness
• Not using environment variables (though recommended)

5. You want to keep your Supabase key secure in a JavaScript project. Which is the best practice to handle the key?

hard

A. Publish the key in your public GitHub repository for easy access

B. Hardcode the key directly in your JavaScript files

C. Store the key in an environment variable and access it in your code

D. Send the key as a query parameter in URLs

Solution

1. Step 1: Understand security best practices for keys

   Keys should not be exposed in code or public places to avoid misuse.

2. Step 2: Use environment variables to keep keys secure

   Environment variables keep keys out of code and can be managed securely.

3. Final Answer:

   Store the key in an environment variable and access it in your code -> Option C

4. Quick Check:

   Use environment variables for secrets [OK]

Hint: Never hardcode keys; use environment variables [OK]

Common Mistakes:

• Hardcoding keys in source code
• Exposing keys publicly in repos
• Passing keys in URLs