Pathwise

Manuals / JavaScript / Chapter 13

F · Pro · advanced · Week 10–11 · Chapter 13 of 14

Reading unfamiliar codebases

Professional work is mostly reading, not writing. Start from entry point (main.js, index.html). Follow imports. Use grep/search for symbols. Debugger breakpoints beat console.log spam. Read tests to learn intended behavior. Leave code better — small rename PRs build trust.

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Step 1 of 5

Find the entry point

package.json "main" or "module". index.html script tags. src/main.js in Vite. Start there; follow one user action end-to-end.

Find the entry pointDrag stickies · tap for tips
Study mapDrag stickies · tap for tipsKeep it shortdrag · tap →Name the waitdrag · tap →Scope locatorsdrag · tap →Trace when stuckdrag · tap →One browser firstdrag · tap →Isolate statedrag · tap →Assert the UIdrag · tap →Retry wiselydrag · tap →Seed datadrag · tap →Close the loopdrag · tap →Keep it shortdrag · tap →Name the waitdrag · tap →Scope locatorsdrag · tap →Trace when stuckdrag · tap →One browser firstdrag · tap →Isolate statedrag · tap →Pathwise hackdrag · tap →Find the entry poidrag · tap →Try thisdrag · tap →Follow the dashed drag · tap →

Do this now

Clone a small open-source vanilla JS or Vite project (<500 lines). Identify entry point in 10 minutes.

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Chapter learning outcomes
  • Entry point tracing
  • Search strategies
  • Debugger usage
  • Reading tests as docs
  • Safe refactoring

Clear these before you leave

Side quest

Architecture sketch

Draw a one-page diagram: modules, data flow, external APIs. No code — boxes and arrows only.