GraphQL Playground and tools - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

What is the primary purpose of GraphQL Playground?

GraphQL Playground is a popular tool used by developers. What is its main purpose?

A To convert SQL queries into GraphQL queries

B To deploy GraphQL servers automatically

C To write and test GraphQL queries interactively

D To monitor server CPU and memory usage

💡 Hint

Think about what developers do when they want to try out queries before coding.

GraphQL Playground lets developers write, test, and explore GraphQL queries in an interactive environment.

❓ query_result

intermediate

What is the output of this GraphQL query in Playground?

Given the schema with a user type having fields id and name, what is the output of this query?

{ user(id: 1) { id name } }

GraphQL

{ user(id: 1) { id name } }

A { "data": { "user": { "id": "1", "name": null } } }

B { "data": { "user": null } }

C { "errors": [ { "message": "Field 'user' not found" } ] }

D { "data": { "user": { "id": 1, "name": "Alice" } } }

💡 Hint

Assume the user with id 1 exists and has the name 'Alice'.

The query requests user with id 1, returning id and name fields. Since user exists, data is returned with those fields.

📝 Syntax

advanced

Which option contains a syntax error in GraphQL Playground?

Identify the GraphQL query that will cause a syntax error when run in GraphQL Playground.

A { user(id: 4) { id name }

B { user(id: 3) { id name } }

C { user(id: 2) { id name } }

D { user(id: 5) { id name } }

💡 Hint

Look for missing or extra characters that break the query structure.

Option A is missing the closing brace '}', causing a syntax error in the query.

❓ optimization

advanced

Which tool helps optimize GraphQL queries by analyzing performance?

Among these tools, which one is designed to help developers optimize GraphQL queries by analyzing their performance and complexity?

A GraphiQL

B Apollo Engine

C GraphQL Voyager

D GraphQL Playground

💡 Hint

This tool provides metrics and tracing for GraphQL APIs.

Apollo Engine helps monitor and optimize GraphQL queries by providing performance metrics and tracing.

🔧 Debug

expert

What error message will GraphQL Playground show for this query?

Given the schema does not define a posts field on the Query type, what error will GraphQL Playground return for this query?

{ posts { id title } }

GraphQL

{ posts { id title } }

A { "errors": [ { "message": "Cannot query field 'posts' on type 'Query'." } ] }

B { "data": { "posts": [] } }

C { "errors": [ { "message": "Field 'posts' is deprecated." } ] }

D { "data": null }

💡 Hint

Think about what happens when you query a field not defined in the schema.

GraphQL Playground returns an error indicating the field 'posts' does not exist on the Query type.