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.

2m ago 0

Bash

Print a Boxed Banner

Wrap a string in a Unicode box for important headers. Auto-sizes to the longest line. Helps milestone messages stand out in long CI logs.

2m ago 0

Kotlin

Parameterized Tests with JUnit 5

JUnit 5 + Kotlin: `@ParameterizedTest` runs the same test body with multiple input rows. `@CsvSource` for inline data, `@MethodSource` for complex args.

2m ago 0

Kotlin

use { } — Auto-Close Resources

`use { }` calls `close()` on any `Closeable` (file, stream, JDBC connection, …) when the block exits — even on exception. Kotlin's try-with-resources.

2m ago 0

Kotlin

Coroutine Timeout with withTimeout

`withTimeout(ms) { ... }` cancels the inner coroutine if it doesn't finish in time and throws `TimeoutCancellationException`. `withTimeoutOrNull` returns null instead.

2m ago 0

Bash

Check Command Exists Before Using It

`command -v` is the portable, fast way to check whether a binary is on $PATH. Avoid `which` (its behavior varies between systems).

2m ago 0

Go

Prepared Statement Reuse

For repeated queries (loops, bulk inserts), prepare once and re-use. The driver caches the parsed query and saves a round trip per invocation.

2m ago 0

PHP

cURL Multipart File Upload

Upload one or more files via multipart/form-data using cURL's CURLFile abstraction. No manual boundary or body construction needed.

2m ago 0

Bash

Multipart File Upload via cURL

Upload one or more files using -F. Optional extra form fields go through the same flag — quote carefully to preserve spaces.

2m ago 0

Bash

Most-Modified Files in Repo

Find the hottest files in a git history — useful for spotting hotspots that need refactoring or extra test coverage.

2m ago 0

Bash

Rotate Logs Manually

If a service doesn't hook into logrotate, you can still rotate a log file yourself in one safe pattern: rename current → .1, truncate the original, signal the process to re-open if needed.

2m ago 0

HTML

Sortable Table (semantic markup + JS hook)

Use `<button>` inside `<th>` and `aria-sort` on the column so screen readers announce sort state. The button is the keyboard-accessible trigger; JS only handles the actual sort.

2m ago 0

TypeScript

Generic Constraints with `extends`

Generics start unbounded — you can't access any properties of `T`. `T extends { … }` adds a constraint so the body can safely use known shape, while callers can still pass in narrower types.

2m ago 0

Java

Atomic File Write (move with ATOMIC_MOVE)

Write to a temp file in the same directory, then `Files.move` with `ATOMIC_MOVE` to the target. Readers never see a half-written file — critical for config / state files.

2m ago 0

PHP

Recursive Directory Walker

Yield every file under a directory using a generator and SPL's RecursiveIteratorIterator. Filter by extension or any other predicate without slurping all paths into memory first.

2m ago 0

Go

iota — Auto-Incrementing Constants (Enums)

Go has no `enum` keyword but `iota` inside a const block gives you the same effect. Each line is the previous expression with iota auto-incremented.

2m ago 0

Python

Context Manager via @contextmanager

Build a custom context manager without writing a class — just a generator with one `yield`. The code before yield runs on enter, after yield runs on exit (even on exception).

2m ago 0

Go

filepath.Walk — Recursive Tree Walk

`filepath.WalkDir` (Go 1.16+) is the modern, faster version. Visit every file/dir under a root; the callback decides whether to skip or process.

2m ago 0

Go

Worker Pool with Channels

Spawn N worker goroutines, feed them tasks over a jobs channel, collect results on a results channel. Idiomatic Go pattern for bounded concurrency.

2m ago 0

Go

select — Multiplex Channel Operations

`select` is like a switch for channels — runs whichever case is ready. Use `default` for non-blocking sends/receives; `case <-time.After(d)` for timeouts.

2m ago 0

Kotlin

tailrec — Tail-Call Optimization

Mark a recursive function `tailrec` and the compiler rewrites it as a loop — no stack frame per call, no StackOverflowError on deep recursion. Function must end with itself as the FINAL expression.

2m ago 0

Kotlin

Companion Objects

A `companion object` inside a class hosts what other languages call "static" members. Methods + properties on the companion are callable as `Foo.bar()`, but unlike static, they're a real object you can extend or implement interfaces on.

2m ago 0

TypeScript

safeJsonParse — Result-Typed

Parse JSON without ever throwing. Returns a Result-like discriminated union so callers must handle both success and failure paths at compile time.

2m ago 0

Bash

Unique While Preserving Order

`sort -u` re-orders. `awk '!seen[$0]++'` is the classic order-preserving dedupe — and it's a single line.

2m ago 0

Go

errors.Join — Aggregate Multiple Errors

Go 1.20+ ships `errors.Join`, which combines multiple errors into one. Stop accumulating errors in a slice and stringifying yourself — use the standard library.

2m ago 0

SQL

INSERT … SELECT — Bulk Copy

Copy/transform rows from a SELECT into another table — the cheapest way to move data within the database. Skip column lists at your peril; positional matching is fragile.

2m ago 0

Java

Stream Basics — filter / map / collect

The fluent pipeline for transforming collections. `filter` keeps matching elements, `map` transforms each one, `collect(toList())` materializes the result.

2m ago 0

SQL

RANK / DENSE_RANK

`RANK` leaves gaps after ties (1, 2, 2, 4); `DENSE_RANK` doesn't (1, 2, 2, 3). `ROW_NUMBER` is always unique. Pick by what tied rows should produce.

2m ago 0

Go

regexp.MustCompile + FindAll

`regexp.MustCompile` panics on a bad pattern at startup — perfect for package-level vars. Use `Find`, `FindString`, `FindAllStringSubmatch` to extract matches and capture groups.

2m ago 0

PHP

Atomic File Write

Write a file in a way that other processes never see a half-written state. Write to a temp file in the same directory, then rename — rename is atomic on POSIX filesystems.

2m ago 0