LAB REPOSITORYPRO CODEBASE

Write-Ahead Log

A tiny durable key-value store that writes JSONL WAL records before applying in-memory state, then replays safe records after a crash.

JavaScriptDifficulty: starter

$node implementations/write-ahead-log/src/demo.js

Key Takeaways & Architecture Lessons

01.The WAL is the durable source of truth for acknowledged writes.
02.Recovery rebuilds memory by replaying complete, checksummed records.
03.A damaged tail is truncated because interrupted appends are expected during crashes.

Full source code for README.md is included in the Pro engineering package.