Build hard Node.js
systems from scratch
with Labs.

Build a parent-process recorder that launches another Node script, injects an in-process probe when needed, and preserves evidence from the run.

• Parent-process launcher with exit, signal, and stdio evidence
• In-process probe for memory, CPU, event loop delay, handles, warnings, and failures
• JSON, HTML, Markdown, and comparison reports

Build a local database with a binary disk format, append-only segment files, direct lookups, corruption checks, recovery, deletes, compaction, and benchmarks.

• Binary record format with checksums and append-only segments
• Indexes, recovery, tombstones, and compaction
• Format docs, recovery reports, and benchmark output

Build a CLI workbench that generates predictable NDJSON, compares whole-file and streaming processors, measures memory, simulates slow consumers, compresses output, and cancels pipelines.

• NDJSON generator, whole-file baseline, and stream pipeline
• Slow sinks, backpressure timeline, gzip mode, and cancellation
• Memory, duration, row count, pressure, and comparison reports

Build a resolver CLI that accepts an importer and specifier, traces lookup decisions, records package metadata, flags CJS/ESM hazards, and writes reports.

• Resolver traces for files, packages, exports, and conditions
• CJS/ESM hazard detection and module cache graph output
• Text, JSON, HTML, and Markdown resolution reports

Build a watch-mode CLI that treats file events as input to verify, scan, hash, diff, rebuild, cache, debounce, and report.

• Recursive scans, metadata snapshots, hashes, and persistent cache files
• Native watch, polling fallback, atomic write normalization, and rebuild queues
• Scan, diff, watch-state, queue, rebuild, and shutdown reports

Build a local task runtime that reads task definitions, schedules work, limits concurrency, records attempts, handles failures as data, and persists state.

• Task validation, scheduling, concurrency limits, retries, and cancellation
• EventEmitter lifecycle events, async iterator progress, persistence, and resume
• State, latest-run, mode, benchmark, and final reports

Build a TCP gateway with a documented binary protocol, client encoder, stateful parser, malformed-frame handling, backpressure-aware sinks, HTTP forwarding, metrics, load testing, and reports.

• Binary frame format, client encoder, TCP parser, and malformed-frame handling
• Backpressure-aware file sink, HTTP forwarding, ACK/error frames, and metrics
• Protocol docs, load reports, and final HTML/Markdown reports