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Rubin Bhandari.
Writing

The Iteration Log.

Practical guides on engineering, design, and the craft of building on the web for curious developers.

The JavaScript event loop, explained with a coffee shop
Featuredjavascript

The JavaScript event loop, explained with a coffee shop

One barista, two queues, and a rule about regulars. A mental model for how JavaScript handles one thing at a time without feeling slow.

Aug 11, 20262 min read
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PM2 and systemd for Node apps: a practical cheatsheetdevops
Sep 19, 20263 min read

PM2 and systemd for Node apps: a practical cheatsheet

Two ways to keep a Node app running after you log out. Commands, unit files, and when to pick which.

nodejsdeploymentdevops
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cURL cheatsheet for API developersapi
Sep 18, 20263 min read

cURL cheatsheet for API developers

The curl flags that cover 95% of API work: methods, headers, bodies, auth, and debugging redirects and TLS. Bookmark it.

apiterminalhttp
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Zero-downtime database migrationsdatabase
Sep 17, 20264 min read

Zero-downtime database migrations

ALTER TABLE locks your biggest table and your deploy waits. The expand/contract pattern migrates a live table without an outage window.

databasesqldeployment
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Template literal types in practicetypescript
Sep 16, 20263 min read

Template literal types in practice

String types that compile. Building event names, CSS variable keys and route patterns out of unions, with the four built-in helpers that do the trimming.

typescripttypes
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Circuit breakers: failing fast when a dependency is downarchitecture
Sep 14, 20264 min read

Circuit breakers: failing fast when a dependency is down

When a downstream service hangs, your service hangs too, and the outage spreads backwards. Circuit breakers contain it. Here's the state machine and a working implementation.

architecturebackendresilience
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Branded types: making invalid states unrepresentabletypescript
Sep 13, 20263 min read

Branded types: making invalid states unrepresentable

UserId and OrderId are both strings, until you pass one where the other belongs. Nominal typing with brands, and the parse-at-the-boundary pattern that makes it work.

typescripttypesarchitecture
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