Dan Harper
Senior Staff Software Engineer IC7 at Meta
London, England, United Kingdom
Summary
🤩
Rockstar🎓
Top SchoolDan Harper is a Senior Staff Software Engineer with 15+ years of hands-on experience building scalable backend systems and polished cross-platform UX at Meta, where he’s led teams across Workplace, Messenger, Horizon Worlds and AI Productivity. He combines deep technical breadth—from low-level C++ and React Native desktop APIs to large-scale data ingestion platforms like BulkTask—with a product-first sensibility that prioritises tiny UX details users notice only when they’re missing. Known for turning slow or failing initiatives into shipping products, he’s orchestrated ambitious migrations (including a company-wide chat migration) and shipped creator-focused features in Horizon Worlds. An active open-source contributor, his commits to high-profile projects like Babel and eslint-plugin-flowtype show a strong grounding in JavaScript compilation and type tooling. Based in London, he balances relentless engineering drive with a knack for simplifying complex requirements and a surprising dedication to chasing cats around the world.
15 years of coding experience
10 years of employment as a software developer
Bachelor’s Degree Web Technologies, Bachelor’s Degree Web Technologies at University of Portsmouth
Stackoverflow
726reputation
103kreached
9answers
4questions
Github Skills (28)
astm10
javascript10
flow-control10
work-flow10
eslint10
type-annotations10
compiler-compiler10
front-end-development10
control-flow10
babel-core10
flowtype10
compiler10
babeljs10
typecript9
jquery9
Programming languages (12)
Github contributions (5)
gajus/eslint-plugin-flowtype
Aug 2016 - Jan 2017
Flow type linting rules for ESLint.
Role in this project:
Full-stack Developer
Full-stack DeveloperContributions:87 commits, 66 PRs, 50 pushes in 5 months
Contributions summary:Dan primarily contributed to the `eslint-plugin-flowtype` repository by implementing and fixing rules related to Flow type annotations. Their work included supporting optional arguments, fixing spacing issues before and after type colons, and applying these spacing rules to object properties and class properties. They also addressed function return type requirements, including arrow functions and async/generator functions, as well as the exclusion of arrow functions from parameter type requirements. The user's contributions focused on improving the linting capabilities for Flow type checking within the codebase.
lintereslintlintingeslint-configlinting-rules
babel/babel
Aug 2016 - Jan 2017
🐠 Babel is a compiler for writing next generation JavaScript.
Role in this project:Back-end Developer
Back-end DeveloperContributions:19 commits, 12 PRs, 1 branch in 4 months
Contributions summary:Dan primarily contributed to the Babel compiler, focusing on enhancements related to Flow type annotations and arrow functions. Their work included bug fixes for generating arrow functions, handling return types, and addressing issues with default arguments in type annotations. Furthermore, the user improved the handling of class properties and object methods, including their return types, within the transpilation process. The commits reflect a deep understanding of JavaScript compilation and type systems.
next-generationbabelflavortownjavascriptast
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