# Marijn Haverbeke Marijn Haverbeke is a Dutch independent programmer based in Berlin, working mostly on programming language theory and developer tooling. He funds his work through sponsorships and direct support rather than a company, and he has been doing it for well over a decade. He is the author of the open-source book *Eloquent JavaScript*, one of the best entry points into the language, first published in 2011 and revised several times since. ## What he built - [[CodeMirror]], the in-browser code editor that powers the [[Obsidian]] editor - [[Lezer]], the incremental parsing system behind CodeMirror 6 syntax handling - [[Acorn]], a JavaScript parser used across a large part of the JS tooling ecosystem - [[ProseMirror]], a structured rich-text editor - [[Wordgard]], a newer rich-text editor built from what he learned maintaining [[ProseMirror]] - Tern, a type inference engine for JavaScript ## Why he's worth studying Look at that list again. One person, sustained over years, sitting underneath an enormous amount of software that other people ship. If you write plugins for [[Obsidian]], you are standing on his work. Two habits stand out. First, he keeps maintaining old projects even while launching their conceptual successors. When he released [[Wordgard]], he stated plainly that ProseMirror maintenance continues. Second, he refuses fake continuity: rather than calling the new editor ProseMirror 2.0, he gave it a different name so nobody would expect a migration path that doesn't exist. That's a healthy model for anyone building in [[Open Source]] for the long run. ## References - https://marijnhaverbeke.nl/ - https://eloquentjavascript.net/ - https://github.com/marijnh - https://code.haverbeke.berlin/ - https://codemirror.net/ - https://prosemirror.net/ - https://wordgard.net/ ## Related - [[CodeMirror]] - [[ProseMirror]] - [[Wordgard]] - [[Obsidian]] - [[Open Source]]