Justin Grant
Product Advisor at ECMA TC39 (the JavaScript standards body)
Berkeley, California, United States
Summary
🤩
Rockstar🎓
Top SchoolJustin Grant is a Bay Area product advisor and founder with 9 years of experience focused on Vertical SaaS, B2B UX, and APIs, helping small product teams translate founder vision into measurable growth. He’s led product, growth, and design at early-stage startups—driving a 3.6x increase in paid signups at UpCodes—and bootstrapped a consumer scheduling startup while mentoring teams at AON3D. As an invited expert at ECMA TC39 he co-leads the open-source JavaScript Temporal effort and has shipped deep compatibility fixes and TypeScript typings for the Temporal polyfill that are headed to browsers and Node.js. He blends hands-on engineering and QA contributions with product strategy, pairing hobbyist-developer curiosity with pragmatic roadmap execution.
10 years of coding experience
26 years of employment as a software developer
B.A., B.A. at University of California, Berkeley
Github Skills (20)
debug10
typescript310
javascript10
ecmascript-610
ecmascript610
temporal10
testing10
typescript10
ecmascript510
typescript210
javascripts10
api10
ecmascript-310
typescript-types10
typescripts10
Programming languages (17)
Github contributions (5)
tc39/proposal-temporal
May 2020 - Jan 2023
Provides standard objects and functions for working with dates and times.
Role in this project:
Back-end Developer
Back-end DeveloperContributions:768 reviews, 208 commits, 240 PRs in 2 years 8 months
Contributions summary:Justin primarily contributed to the development of the Temporal proposal by fixing bugs and improving the codebase. They addressed an infinite loop issue in Chrome's `GetFormatterParts` function, introduced and refined TypeScript types for the polyfill, and removed the `balance` disambiguation option from non-Duration types. The user also made adjustments to calendar-related functionality and other minor updates to the polyfill.
datetimedates-and-timesdate-parsertimeagotimes
tc39/test262
Oct 2021 - Jan 2023
Official ECMAScript Conformance Test Suite
Role in this project:QA Engineer / Test Automation Engineer
QA Engineer / Test Automation EngineerContributions:32 reviews, 8 commits, 17 PRs in 1 year 2 months
Contributions summary:Justin primarily contributed to the test suite for the ECMAScript Conformance Test Suite. Their commits include reverting changes to tests, verifying the non-writeable nature of prototype properties, and fixing test failures under specific Node.js versions. These changes demonstrate a focus on maintaining the accuracy and reliability of the test suite, specifically related to Temporal objects. Furthermore, the user ensures the tests' compatibility with various environments by addressing compatibility issues across Node.js versions, which involves modifying existing test cases.
javascriptconformancetc39typescripttests
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