Joel Feenstra
Senior Software Engineer at The MathWorks
Framingham, Massachusetts, United States
Summary
👤
Senior🎓
Top SchoolJoel Feenstra is a Senior Software Engineer with 13 years at The MathWorks, building large Java-based servers and complex JavaScript client applications while advancing web-related tooling. He combines systems-level expertise in Kubernetes and Linux with strong language fluency in Go, C++, Java, and MATLAB, enabling him to tackle both infrastructure and application challenges. A persistent open-source contributor, Joel improved critical AST-querying and linting libraries (notably esquery and eslint) by adding sophisticated selector features and expanding test coverage to catch subtle unreachable-code patterns. His background in mechanical engineering and early work in test and deployment tooling give him a pragmatic, measurement-driven approach to software quality. Based in Framingham, MA, he brings long-term institutional knowledge, refactoring discipline, and a knack for turning complex parsing and testing requirements into maintainable implementations.
12 years of coding experience
5 years of employment as a software developer
MA, Mechanical Engineering, MA, Mechanical Engineering at Michigan Technological University
Github Skills (14)
astm10
css-selectors10
static-code-analysis10
javascript10
eslint10
ecmascript10
testing10
nodejs9
regular-expression9
unit-testing9
computer-engineering8
data-structure7
data-structures7
algorithms7
Programming languages (5)
Github contributions (5)
estools/esquery
Jul 2013 - Nov 2013
Role in this project:
Full-stack Developer
Full-stack DeveloperContributions:37 commits, 1 comment in 3 months
Contributions summary:Joel significantly enhanced the `esquery` library by implementing a range of selector features, including sibling, child, adjacent, nth-child, nth-last-child, and attribute-based selectors. They refactored the parser, adding support for compound selectors and improved the handling of complex selector patterns. Furthermore, the user integrated tests for tokenization and processing of selectors, as well as implementing features like :matches and :not pseudo-classes. They added support for regular expression and type-based attribute matching, as well as a subject selector, and case-insensitive type matching.
queryjavascriptastestreeecmascript
eslint/eslint
Jul 2013 - Jul 2013
Find and fix problems in your JavaScript code.
Role in this project:QA Engineer / Test Automation Engineer
QA Engineer / Test Automation EngineerContributions:6 commits in 4 days
Contributions summary:Joel contributed to the `eslint/eslint` repository by modifying and expanding the test suite for the `no-unreachable` rule. Their commits focused on adding new test cases to cover scenarios where unreachable code is present due to `return`, `throw`, `break`, and `continue` statements, within both regular blocks and switch statements. The user's work ensures the linter correctly identifies and flags unreachable code paths within JavaScript code, improving code quality and preventing potential runtime errors. Furthermore, the user refactored code to use a switch statement, improving maintainability.
linterfixeslintproblemsjavascript
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