Rust

impl Trait — Static Dispatch Returns

When you want to return a complex iterator chain or closure, you don't need to spell out the type. `impl Trait` lets the compiler infer the concrete type while exposing only the API contract.

3h ago 0

Kotlin

inline Functions — Zero-Cost Lambdas

`inline fun` copies the body (including lambda bodies) into the call site at compile time. Result: no `Function` object allocated for the lambda; `return` from inside the lambda exits the enclosing function.

3h ago 0

Kotlin

Compose Modifier Chain

`Modifier` is how you customize composables — padding, click handlers, background, size, alignment. Order matters: each modifier wraps the previous one.

3h ago 0

Kotlin

Exposed — Kotlin-First ORM

JetBrains' Exposed combines a SQL DSL with a lightweight ORM. Either style is fully type-safe; both compile to plain SQL.

3h ago 0

Go

time.Ticker — Periodic Tasks

`time.NewTicker(d)` fires on a channel every `d` interval. Combine with select + a done channel for a clean way to run periodic work that can be cancelled.

3h ago 0

PHP

Partition Array Into Two Buckets

Split an array into [matches, non-matches] using a predicate callback. Single pass, preserves order, returns two lists.

3h ago 0

Python

sqlite3 with Row Factory + Context

Stdlib sqlite3 is fine for embedded / small workloads. Use `with conn:` for automatic commit/rollback, and a row_factory so you get dicts (or namedtuples) instead of bare tuples.

3h ago 0

Bash

Heredoc with Variable Interpolation Control

Heredocs are the cleanest way to embed multi-line text. Unquote the delimiter to allow variable expansion; QUOTE it to keep the body literal (no $foo expansion).

3h ago 0

Bash

Count Occurrences of a Pattern

Several ways to count matches: lines containing X, total matches across a file, matches grouped by capture, etc.

3h ago 0

Java

Builder Pattern

For objects with many optional parameters, a Builder beats a constructor with 12 args (or a half-initialized object you have to call setters on). Method chaining + a `build()` step that validates.

3h ago 0

HTML

Navigation with aria-current

Use `<nav>` for primary navigation. Mark the currently-active link with `aria-current="page"` — screen readers will announce it, and you get a free CSS hook with `[aria-current]`.

3h ago 0

Python

Dataclass with frozen + slots + defaults

Modern dataclass essentials: immutable instances (frozen=True), tighter memory + faster attribute access (slots=True), and default_factory for mutable defaults so every instance gets its own list.

3h ago 0

Bash

Tail Last N Lines (no `tail` shortcuts)

`tail -n 20` works for any case where tail is available. The pure-bash version below is useful inside containers or rescue shells where coreutils is missing.

3h ago 0

Bash

Filter Lines by Regex

grep -E (extended regex) is the right tool 95% of the time. Combine -i (case-insensitive), -v (invert), -n (line numbers), -B/-A (context lines).

3h ago 0

Rust

unsafe — When and How

Most Rust is safe. `unsafe` only lets you do 5 things the compiler can't check (raw pointer deref, mutable static, unsafe fn / trait, FFI, union access). Wrap unsafe operations in safe abstractions.

3h ago 0

Go

Interface Segregation — Small Interfaces

"The bigger the interface, the weaker the abstraction." Go encourages small, focused interfaces (often just one method) — io.Reader, io.Writer, fmt.Stringer. Define them at the consumer side.

3h ago 0

Go

Benchmarks with testing.B

`BenchmarkXxx(b *testing.B)` functions are run by `go test -bench`. `b.N` is the loop count the framework auto-tunes; report results in ns/op, allocs/op.

3h ago 0

HTML

RTL (Right-to-Left) Document

Set `dir="rtl"` on the root element for languages that read right-to-left (Arabic, Hebrew, Persian). The browser flips text alignment, scroll, and form controls automatically. Use `dir="auto"` to let user-generated text decide per-block.

3h ago 0

Kotlin

apply — Configure Object, Return Itself

`x.apply { ... }` runs the block with `x` as `this` (so you call methods/set properties directly) and returns `x`. The canonical builder-style configuration.

3h ago 0

Kotlin

Jetpack Compose — Basic Composable

Compose is Android's modern declarative UI toolkit. A `@Composable` function describes UI; the runtime re-runs it when inputs change. Replaces XML layouts entirely.

3h ago 0

Python

NewType for Nominal IDs

Python's type system is structural — `UserId` and `PostId` are both just `int` unless you ask otherwise. `NewType` creates a distinct type with zero runtime cost for static checking only.

3h ago 0

Bash

Convert Between Timezones

Set TZ inline to print a date in a specific timezone, then read with another TZ. Avoids messing with the system timezone.

3h ago 0

Rust

fold / reduce / scan

`fold` is the general aggregator: starts from an accumulator, applies a fn to each item. `reduce` uses the first item as the seed. `scan` yields intermediate accumulator values.

3h 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.

3h ago 0

Rust

Result Combinators + the ? Operator

`Result<T, E>` chains like `Option`. The `?` operator unwraps `Ok` or early-returns the `Err`, converting via `From` so callers can use one error type for many sources.

3h ago 0

Go

Custom Generic Constraints

Type constraints are interfaces with type sets. Use them to express "any numeric" or "any ordered" without resorting to `any`.

3h ago 0

TypeScript

Capitalize / Title-Case

Two common case transforms. `capitalize` for the first letter only; `titleCase` for every word, with small "stop words" left lowercase except at the edges.

3h ago 0

Python

Async Retry with Exponential Backoff

Retry an async operation up to N times, doubling the wait each attempt with random jitter to avoid thundering herd. Predicate controls retryability so 4xx errors stop immediately.

3h ago 0

Java

java.time — Instant, LocalDate, ZonedDateTime

Java 8's `java.time` package replaced the broken `Date`/`Calendar`. Three types you actually use: `Instant` (UTC moment), `LocalDate` (date with no tz), `ZonedDateTime` (date+time in a zone).

3h 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.

3h ago 0