February 20, 2026
Code map or it didn’t happen
Untapped Way to Learn a Codebase: Build a Visualizer
Programmer maps a code maze, and the crowd shouts: show us the tool
TLDR: A developer learned a sprawling software project by building a visual map of it, sparking cheers and demands to “share the tool.” Commenters split between veterans saying “we’ve done this for years,” realists warning most projects lack clean histories, and optimists claiming AI could make this the new normal.
A developer tried a bold way to learn a giant codebase: build a visual “map” of how everything connects, then poke it with safe, tiny changes until the picture makes sense. Using a bug report as a starting point, they dove into Next.js and its new Rust-powered bundler, Turbopack, not to fix anything—just to understand it. The post reads like a guided tour through a labyrinth, swapping “read every file” for “draw the map, then explore.” It’s part detective work, part science fair, and very much “don’t panic.”
But the comments? On fire. The top mood: hand it over. Fans begged to try the visualizer—“Is there a demo? Is there code?”—while reverse-engineering vets chimed in with a knowing nod: this “Graph View” is a classic spy tool finally going mainstream. A grizzled voice dropped the reality check: you’ve got it easy with tidy commit history and bug reports; most of us are spelunking in mystery caves. Then came the future-shock crowd, cheering that AI coding tools could supercharge this, turning code-reading into code-mapping on demand. Meme patrol showed up too: “CSI: Code Scene,” “string-and-pins conspiracy board,” and the eternal refrain—“code map or it didn’t happen.” The only real fight? Whether this is a fresh breakthrough or a remix of old-school tricks with splashier paint.
Key Points
- •The author proposes a method to learn large codebases by setting goals, experimenting with edits, fixing incidental issues, reading to answer specific questions, and building a visualizer.
- •The demonstration targets the Next.js repository, focusing on its Rust-based Turbopack bundler.
- •Starting from a main entry point is discouraged; instead, the author surveys repository structure to find a manageable entry.
- •Turbopack contains its own set of Rust crates, with 54 crates counted, highlighting its breadth.
- •A minimal reproducible example derived from a bug report is used to guide exploration and inform the eventual visualizer.