9 min read
The Array.sort() Bug Only Numbers Above 9 Trigger
Array.sort() with no compare function left 9 of 20 sorted numbers in the wrong place. One compare function…
The Lab · Written in the open · Tagged Tutorials
Lab.
Working notes from the studio. The tools I build, the workflows I keep, the mistakes I paid for.
62 entries · latest 2026-11-06
Latest entry
String Concatenation vs Array Join: I Timed the Old Advice
I timed string concatenation against array push and join across four loop sizes, and the old quadratic-cost advice did not hold.
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TLDR
This entry in one minute
- I timed string += against array push then join at four loop sizes in Node 22
- At 1 million iterations, += finished in 339ms against 437ms for push and join
- The two methods tied at 10,000 and 100,000 iterations, within a few percent either way
All entries · Tutorials
9 min read
Claude Code 2.1.311: Ultrathink Now Hits xhigh Via the API
Claude Code 2.1.311 and 2.1.312 ship ultrathink at xhigh via the API, a renamed 5-hour usage limit, and…
9 min read
Debugging a Memory Leak in a Long-Running Node Process
A healthy Node process has a sawtooth memory graph; a rising floor means a leak
9 min read
Scheduled Jobs and Time Zones: The Midnight Bug I Keep Seeing
Cron runs in UTC by default, so a "midnight" job can fire on the wrong local day
8 min read
Request Validation at the Edge: A Minimal Pattern I Reuse
Reject bad requests at the edge before they touch real logic or a database
9 min read
I Found the Exact Recursion Depth That Crashes Node
Plain recursion crashed at exactly 9,275 calls deep. An iterative rewrite handled 215 times that depth in 13ms.
9 min read
Binary Search vs Array.includes() on a 50,000-Row Catalog
A one-line swap took a 50,000-row lookup from 408ms to under 1ms. I measured both methods instead of…
9 min read
Writing Idempotent Webhooks: Patterns That Survive Retries
Every webhook arrives twice eventually, so design for it from day one
9 min read
git bisect run on 1,000 Commits: 10 Runs and 3 Wrong Answers
I planted a bug in a 1,000-commit repo. git bisect run found it in 10 runs, after three…
9 min read
Claude Code Just Removed the Subagent Spawn Cap
Version 2.1.224 removes the 200 subagent cap, adds self hosted runners, cross session messaging, and tighter sandbox credential…
9 min read
MCP Goes Stateless: What the 2026-07-28 Spec Actually Changes
MCP dropped its session handshake for a stateless core, hardened OAuth, and made tool lists cacheable, with SDK…