Dayong Lee
Frontend Developer at Toss Bank(토스뱅크)
Seoul, South Korea
Summary
🤩
Rockstar🎓
Top SchoolDayong Lee is a Frontend Developer based in Seoul with 7 years of experience building practical, user-focused web applications. Currently at Toss Bank, he balances pragmatic engineering with continuous learning to deliver sustainable, maintainable front-end solutions. Academically strong in computer science, he holds degrees from Sungkyunkwan University and Kyungmin College with high GPAs. An active open-source contributor, Dayong has improved performance-oriented JavaScript utilities in the well-regarded toss/es-toolkit project, enhancing functions like camelCase, clone, and includes. He emphasizes developer experience (DX) and clean software engineering (SWE) practices, favoring fundamentals that scale. Colleagues describe him as a steady problem-solver who combines attention to detail with an eye for efficiency.
7 years of coding experience
Bachelor's degree, Computer Science and Engineering, 4.0/4.5, Bachelor's degree, Computer Science and Engineering, 4.0/4.5 at 성균관대학교Computer Software Engineering, 4.5/4.5, Computer Software Engineering, 4.5/4.5 at Kyungmin College
Github Skills (6)
text-manipulation10
data-manipulation10
javascript10
strings10
manipulate10
manipulation10
Programming languages (4)
Github contributions (5)
toss/es-toolkit
Jul 2024 - Apr 2025
A modern JavaScript utility library that's 2-3 times faster and up to 97% smaller—a major upgrade to lodash.
Role in this project:
Back-end Developer
Back-end DeveloperContributions:70 reviews, 123 PRs, 33 pushes in 8 months
Contributions summary:Dayong primarily contributed to enhancing the `es-toolkit` library. Their work focused on implementing various utility functions in the `compat` layer, including functions for string manipulation like camelCase and replace, and functions for object utility like defaults and iteratee. Furthermore, the user added functionality for array manipulation, specifically the includes method. The contributions also included improving existing functionalities, for example the clone method, to handle additional data types.
dayongkr/dayongkr.github.io
Dec 2020 - Mar 2023
Contributions:194 pushes, 3 branches, 28 comments in 2 years 3 months
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