SQL

RETURNING — Get Back What You Wrote

PostgreSQL `RETURNING *` returns the rows affected by an INSERT/UPDATE/DELETE — no separate SELECT round-trip needed. SQL Server has `OUTPUT`; MySQL added `RETURNING` in MariaDB and 8.0.31+.

1m 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.

1m ago 0

PHP

HTTP Retry with Exponential Backoff

Wrap any HTTP call in a retry loop with capped exponential backoff and jitter. Retries on 5xx / network errors but not on 4xx (those won't fix themselves).

1m ago 0

Go

Sentinel Errors (var ErrFoo = errors.New)

Sentinel errors are package-level singletons you can compare against with `errors.Is`. Use sparingly — they're part of your package's API surface and changing them is a breaking change.

1m ago 0

Go

Error Wrapping with %w

`fmt.Errorf` with `%w` wraps an inner error inside an outer one, preserving the chain. Callers can use `errors.Is` / `errors.As` to inspect any level of the chain.

1m ago 0

Rust

Untyped JSON with serde_json::Value

When you don't know the JSON shape up-front, parse into `serde_json::Value` and navigate via index / get(). Type-safe pattern matching converts back to Rust types.

1m ago 0

Rust

Read a File — Whole / Lines / Bytes

Three common patterns: load it all into memory, iterate line-by-line, or stream bytes. Pick by file size — `read_to_string` is convenient but bad for huge files.

1m ago 0

Rust

match with Guards, Ranges, and Bindings

`match` arms can have `if` guards, range patterns (`1..=5`), bindings (`x @ pattern`), and ORs (`A | B`). Combine them for very expressive dispatch.

1m ago 0

Bash

Cron Entry From Script

Append a cron job idempotently — grep first to avoid duplicates on re-run. Doesn't require editing files manually.

1m ago 0

Python

Retry Decorator with Exponential Backoff

Generic retry decorator: attempts × base delay, exponential ramp, random jitter. Filter retryable exceptions via the `on` tuple so logical errors aren't retried.

1m ago 0

TypeScript

Bearer-Auth Fetch Wrapper

Wrap fetch so every request automatically attaches an Authorization: Bearer header from a token getter. Token can be a static string or a function (useful for refreshing).

1m ago 0

Kotlin

Result Type — Safe Error-Returning APIs

`Result<T>` wraps "success or thrown exception" without forcing the caller into try/catch. `runCatching { ... }` is the standard producer.

1m ago 0

Bash

Get Public IP Address

Several free services return your public IP as plain text. Useful when scripts running behind NAT need to know what address the outside world sees.

1m ago 0

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.

1m ago 0

Kotlin

kotlin.test — Basic Tests

`kotlin.test` is the multiplatform test stdlib. `@Test` marks a test; `assertEquals`, `assertTrue`, `assertFailsWith` are the workhorses.

1m ago 0

Kotlin

with — Scope an Existing Object

`with(x) { ... }` is `run` flipped: the receiver is the first argument. Reads naturally when you're doing several things to an existing object without chaining.

1m ago 0

Kotlin

Sealed Interfaces (Kotlin 1.5+)

Like sealed classes, but for interfaces — and a class can implement multiple sealed interfaces. Cleaner state modeling when you want "this is both a Loadable and a Cacheable".

1m ago 0

SQL

Conditional Aggregation (FILTER / CASE)

Count or sum subsets of rows in a single GROUP BY pass. PostgreSQL has the cleaner `FILTER` clause; everyone else uses `SUM(CASE WHEN ...)`.

1m ago 0

Rust

String vs &str — The Cheat Sheet

`String` is an owned, growable heap allocation; `&str` is a borrowed view into a UTF-8 buffer. Function params should usually take `&str`; return types use `String` when ownership is needed.

1m ago 0

Bash

Read File Line-By-Line (the safe way)

The classic `for line in $(cat file)` is wrong — it word-splits and globbing fires on filenames. Use `while IFS= read -r line` with input redirection.

1m 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).

1m ago 0

JavaScript

Throttle

Ensures a function is called at most once per specified time interval, no matter how many times the trigger fires. Ideal for scroll listeners, mousemove handlers, and window resize events where you need regular updates but not every single frame.

1m ago 0

Kotlin

Channel — Coroutine Communication

A `Channel<T>` is a coroutine-safe queue — producer side sends, consumer side receives. Bounded buffer applies backpressure. Use Flow when broadcasting; use Channel for hand-off between coroutines.

1m ago 0

HTML

Open Graph + Twitter Card Tags

How your page renders when shared to Facebook, LinkedIn, Slack, Discord, X. Every public page needs these — they dramatically improve click-through on shares.

1m ago 0

SQL

ARRAY_AGG and JSON_AGG (PostgreSQL)

Roll up grouped rows into a PostgreSQL array or JSON array — often a faster replacement for the application doing the same "group children under parent" join.

1m ago 0

Java

Files.readString / readAllLines

`java.nio.file.Files` shipped these convenience helpers in Java 8/11. Way cleaner than the legacy `FileReader` + `BufferedReader` ceremony for small/medium files.

1m ago 0

Bash

Wait For Service With Timeout

Block until a TCP port accepts connections, with a deadline. Used everywhere in docker-compose entrypoints — wait for the DB to be ready before running the app.

1m ago 0

JavaScript

Slugify String

Converts any string into a URL-safe slug: lowercases it, replaces accented characters with ASCII equivalents, strips all non-alphanumeric characters (except hyphens), and collapses multiple hyphens into one. Ideal for generating URL slugs from blog titles, product names, or user input.

1m ago 0

Rust

mpsc Channel Between Threads

`std::sync::mpsc` is the standard cross-thread channel. Multiple producers, single consumer. Send any `Send` type; the receiver blocks on `recv()` until something arrives.

1m ago 0

JavaScript

Create Element Helper

A concise helper for creating DOM elements with attributes, properties, styles, event listeners, and children in one call — similar to hyperscript or JSX without a build step. Eliminates repetitive createElement / setAttribute / appendChild chains and keeps DOM construction code readable.

1m ago 0