Tags
#php
#kotlin
#bash
#go
#sql
#rust
#typescript
#html
#java
#python
#files
#utils
#strings
#http
#concurrency
#async
#json
#arrays
#security
#types
#crypto
#database
#dates
#format
Go
sync.Once — Lazy One-Time Initialization
Run a function exactly once, even from many goroutines. Standard pattern for lazy singletons, expensive setup, and one-time configuration.
@admin
Kotlin
lazy — Lazily Computed val
`by lazy { ... }` runs the block on first access, caches the result. Default mode is thread-safe (synchronized). Perfect for expensive initialization where you might never need the value.
Kotlin
coroutineScope and Structured Concurrency
`coroutineScope { }` waits for ALL its children before returning. If any child throws, the others are cancelled. The cornerstone of structured concurrency — no leaked coroutines.
Kotlin
async / await for Parallel Results
`async` returns a `Deferred<T>` — like a Future. Use it when you need a RESULT back, in parallel. Call `.await()` to get the value (suspends until ready).
Kotlin
Coroutines — suspend Function Basics
`suspend fun` can be paused and resumed without blocking a thread. Call only from another `suspend` function or a coroutine builder (`launch`, `runBlocking`, `async`).
Rust
Atomic Counter (lock-free)
For shared counters and flags, `AtomicU64` / `AtomicBool` etc. are much faster than `Mutex`. Operations like `fetch_add` are single CPU instructions on most architectures.
PHP
Constant-Time String Compare
Compare two strings in constant time to avoid timing-attack leaks when checking secrets like API keys, session tokens, or HMAC signatures. Always use hash_equals — never ===.
Kotlin
windowed and chunked
`chunked(n)` splits a list into NON-overlapping pieces of size n. `windowed(n)` slides a fixed-size window across — overlapping. Useful for moving averages, n-grams, batch APIs.
Go
Minimal net/http Server
The standard library ships a production-quality HTTP server. `http.HandleFunc` registers a function; `http.ListenAndServe` blocks forever serving requests.
PHP
Singleton Trait
A reusable trait that turns any class into a lazily-instantiated singleton with a single ::instance() accessor. Throws on clone/wakeup to prevent accidental duplication.
SQL
Generated / Computed Columns
A column whose value is derived from other columns and maintained automatically. PostgreSQL has STORED (persisted) and MySQL adds VIRTUAL (computed on read). Saves you from triggers for derived data.
Go
Pipeline (channel chain)
A pipeline is a chain of stages connected by channels — each stage runs in its own goroutine. Classic Go pattern for streaming transformations with backpressure built in.
HTML
Textarea with Character Counter
Combine `maxlength` (hard cap) with a small JS-driven live counter. Browsers won't let users paste past `maxlength`, so this is purely UX feedback.
SQL
date_trunc — Bucket Times into Hours/Days/Weeks
`date_trunc('day', ts)` rounds a timestamp down to the start of the day. Use for time-series GROUP BYs — daily/weekly/hourly buckets without messy arithmetic.
Java
Immutable Collections — List.of / Map.of
Java 9+ static factory methods return immutable collections with no nulls allowed. Concise, fast, and safer to share across threads or APIs than mutable equivalents.
PHP
Unique by Callback
Like array_unique, but the uniqueness test is a callback that returns the key to dedupe by. Useful for "unique by ID" or "unique by lowercased email" across arrays of objects/rows.
HTML
File Upload (single, multiple, drag-and-drop)
`accept`, `multiple`, and `capture` give you a lot of polish without any JavaScript. Wrap the input in a styled label for a custom-looking drop zone.