Enhance Productivity and Code Quality GH-300 Practice Questions (Page 2)

Questions 6–10

1. 6application · easy

   A developer is writing a SQL query to find duplicate email addresses in a `users` table. They are unsure of the exact `GROUP BY` and `HAVING` syntax. They want to avoid opening a browser to search for the syntax. What is the best way to get the correct query?

   • AOpen a SQL reference website and copy a similar query.
   • BType a comment '-- find duplicate emails' above the query and accept Copilot's suggestion.
   • CAsk Copilot to generate sample data for the users table.
   • DWrite the query without HAVING and test it.
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2. 7application · easy

   A developer is working on a TypeScript project and needs to remember the exact syntax for the `Array.prototype.reduce` method with an initial value. They are not sure if the initial value goes before or after the callback. What is the fastest way to get the correct answer without leaving the editor?

   • AOpen a browser and search for the MDN documentation.
   • BAsk a colleague in a chat application for the syntax.
   • CType a comment like '// reduce with initial value' and let Copilot suggest the code.
   • DWrite the code without an initial value and test it.
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4. 8expert · hard

   A team is modernizing a legacy C# codebase that uses `ArrayList` and `Hashtable` to use `List<T>` and `Dictionary<TKey, TValue>`. The codebase has hundreds of files, and the team wants to minimize risk of behavior changes. They have a comprehensive test suite. What is the best strategy using GitHub Copilot?

   • AManually replace all `ArrayList` with `List<object>` and `Hashtable` with `Dictionary<object, object>`.
   • BAsk Copilot to convert the entire codebase in one prompt.
   • CRefactor file by file, selecting each usage and asking Copilot to convert it, running the test suite after each file.
   • DUse Copilot to generate new classes that wrap the old collections, then replace usages gradually.
   Reveal Solution Discussion Select an answer first
5. 9foundation · easy

   What is a common way to ask GitHub Copilot to explain a piece of unfamiliar code?

   • ARight-click the code and choose 'Get Explanation'.
   • BPress Ctrl+Shift+P and run 'Explain Code'.
   • CSelect the code and type a comment like '# explain this code'.
   • DOpen a new terminal and type 'copilot explain'.
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6. 10application · medium

   A developer is refactoring a large JavaScript function that handles user authentication. The function is 150 lines long, mixes validation, database queries, and session management. The developer wants to extract the validation logic into a separate function while keeping behavior identical. What is the best approach using GitHub Copilot?

   • AAsk Copilot to generate documentation for the current function instead of refactoring.
   • BSelect the validation lines, open the Copilot chat, and prompt: 'Extract this into a separate function named validateCredentials'.
   • CManually copy the validation lines to a new function and hope the rest still works.
   • DDelete the validation lines and ask Copilot to regenerate the entire function from scratch.
   Reveal Solution Discussion Select an answer first