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Jaehyeon Kim

PROFILE

Jaehyeon Kim

Worked on the skkuding/codedang repository, delivering backend features and improvements focused on contest scoring, test submission workflows, and system reliability. Over five months, implemented enhancements such as per-problem and total score retrieval, scalable testcase judging with parallel processing, and GraphQL-based paginated queries for contest submissions. Applied TypeScript, NestJS, and Prisma to enforce data integrity through runtime validation, standardized test submission identifiers, and improved error handling. Maintained code quality by refactoring deprecated features, improving documentation with JSDoc, and tightening repository hygiene. Prioritized maintainability and analytics accuracy, enabling more reliable contest operations and streamlined admin workflows for the platform.

Overall Statistics

Feature vs Bugs

64%Features

Repository Contributions

16Total
Bugs
4
Commits
16
Features
7
Lines of code
1,211
Activity Months5

Work History

March 2025

1 Commits

Mar 1, 2025

March 2025 monthly summary for skkuding/codedang: Focused on data accuracy improvements in test submission categorization and maintaining robust backend data retrieval. No new features delivered this month; primary work targeted bug fixing and analytics reliability.

February 2025

4 Commits • 1 Features

Feb 1, 2025

February 2025 (skkuding/codedang): Focused on stability, data integrity, and backend simplification. Key outcomes include standardized test submission identifiers across cache and DB, resolution of an infinite judging loop on errors, and removal of the deprecated code-draft feature. These changes enhance reliability, data accuracy, and maintainability, delivering clear business value for the judging pipeline and related analytics.

January 2025

4 Commits • 3 Features

Jan 1, 2025

January 2025 monthly summary for skkuding/codedang focused on strengthening data integrity, enriching admin capabilities, and enabling scalable data retrieval for contest submissions. Delivered targeted backend features with validation, sorting, and GraphQL-based pagination to support admin workflows and reporting.

December 2024

2 Commits • 1 Features

Dec 1, 2024

December 2024 monthly summary for the skkuding/codedang repository. Delivered scalable testcase judging improvements and repository hygiene fixes that reduce noise, improve stability, and enable parallel processing. Focused on business value by tightening resource usage, speeding test evaluation, and maintaining a clean, production-ready codebase.

November 2024

5 Commits • 2 Features

Nov 1, 2024

Concise monthly summary for 2024-11 focusing on backend work and business impact. Key features delivered: - Contest scoring data enhancements: added per-problem scores and total scores to contest data retrieval; introduced major field to contest-score-summary API; cleaned data retrieval and calculations to improve reliability. - Backend admin documentation improvements: added JSDoc comments across contest, group, and storage modules to improve maintainability and traceability. Major bugs fixed: - Bug fix: ignore submissions for problems not included in a contest to prevent scoring inaccuracies in contest results. Overall impact and accomplishments: - Improved data accuracy and reliability for contest scoring, enabling fairer rankings and better analytics for organizers and participants. - Enhanced developer productivity and onboarding through better API clarity and code documentation; reduced maintenance burden. Technologies/skills demonstrated: - Backend data modeling and API design (JS/TS), data retrieval optimization, and reliability engineering. - Code hygiene and maintainability (JSDoc documentation, API traces). - Collaboration and traceability through linked commits and PR hygiene.

Activity

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Quality Metrics

Correctness90.0%
Maintainability87.6%
Architecture83.8%
Performance81.8%
AI Usage21.2%

Skills & Technologies

Programming Languages

GoGraphQLHCLSQLTypeScript

Technical Skills

API DevelopmentAPI TestingBackend DevelopmentCachingClass-validatorDTO ValidationDatabase ManagementDatabase QueryingDocumentationError HandlingGitGraphQLInfrastructure ManagementJSDocNestJS

Repositories Contributed To

1 repo

Overview of all repositories you've contributed to across your timeline

skkuding/codedang

Nov 2024 Mar 2025
5 Months active

Languages Used

GraphQLTypeScriptGoHCLSQL

Technical Skills

API DevelopmentAPI TestingBackend DevelopmentDatabase QueryingDocumentationGraphQL