01
iOS and Android
Concurrency, lifecycle and authentication issues in Swift and Kotlin.
Life / Swift / Kotlin / TypeScript / APIs
Programming tutorials
Step-by-step software tutorials centered on runnable code, debugging decisions, edge cases and explicit limitations.
Try this / Practical field guide
How to verify a programming tutorial
A checklist for evaluating code samples, including the linked ZombieMutex references.
- Record runtime, language, dependencies and exact setup prerequisites.
- Reproduce the initial failure before applying the fix.
- Run a positive case, malformed input and a relevant boundary or retry case.
- Identify anything omitted, including authorization or production hardening.
- Publish commands and resulting output only after actually executing them.
A space for the things I want to share
Inside this collection
02
Backend APIs
Retries, idempotency, authorization and request contracts.
03
Testing
Positive paths, malformed input, boundary cases and regression checks.
Hands-on resources & related guides
Stories / Notes / Work in progress
Notes & stories
The first note belongs here.
No personal programming tutorials stories have been published in this collection yet. This section automatically fills with my own approved posts, notes, recipes, or build logs as I add them.
Visit the Life notebookPhotography / Original media
Photos & visual notes
A spot for the first photograph
Original photos only, with descriptive captions
Stories behind the images
Details and context, not stock or invented travel photos
Photo entries appear automatically after original pictures and captions are approved and added to the Life notebook.
Engineering / Inspectable examples
Code samples
Small educational examples, not customer code or claims of deployed robotics, firmware, or backend systems. Open any sample for its checks, source references, and limitations.
TypeScript / Tested teaching helper
Calculate a bounded retry delay
export function retryDelayMs(attempt: number, capMs = 8000): number {
const safeAttempt = Number.isFinite(attempt) ? Math.max(0, Math.min(12, Math.floor(attempt))) : 0;
const safeCap = Number.isFinite(capMs) ? Math.max(0, Math.floor(capMs)) : 8000;
return Math.min(safeCap, 250 * 2 ** safeAttempt);
}Cap exponential retry delays and let the caller enforce a total deadline.
TypeScript / Tested teaching helper
Separate identity from resource authorization
interface Decision { authenticated: boolean; authorized: boolean; integrityOk: boolean }
export function canMutateResource(input: Decision): boolean {
return input.authenticated && input.authorized && input.integrityOk;
}A client or attestation verdict cannot grant access to someone else's object.
Already on the site / Related material