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
Kotlin
kotlinx.serialization — JSON Basics
Compile-time code generation for JSON serialization. Annotate `@Serializable` on a data class; `Json.encodeToString` and `Json.decodeFromString` are typed.
@admin
Java
Optional with Streams
`Optional::stream` (Java 9+) bridges optionals into the Stream API — collect all the `Some` values from a list of optionals, drop the empties, in one pipeline.
Go
sql.NullString — Nullable DB Columns
Plain `string` can't represent SQL NULL. Use `sql.NullString` (and its siblings `NullInt64`, `NullBool`, etc.) for columns where NULL is a real value distinct from empty.
Rust
Move vs Borrow — the Core Rule
Rust's ownership model: passing a value transfers ownership (move); taking a `&value` lets you read without taking ownership; `&mut value` lets you modify without taking ownership. Only one mutable borrow OR many immutable borrows at a time.
HTML
Comment / Review Markup with Schema
Comments and reviews can also have Schema.org markup. The `Review` type appears under products in Google search results with star ratings; `Comment` is for general user feedback.
Bash
Background Jobs + wait
Run several commands in parallel with `&`, then wait for all of them with `wait`. Collect exit codes via $! and check after wait returns.
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.
PHP
Parse Link Header for Pagination
Parse the standard HTTP Link header (RFC 5988) into a relation → URL map. Lets you follow rel="next" pagination in APIs like GitHub without manually building URLs.
Go
strconv — String ↔ Number Conversions
`strconv.Atoi` / `Itoa` for the common int<->string case; `ParseFloat`, `ParseBool`, `Quote` for everything else. Always handle the error — strings can be anything.
Kotlin
Room — Android Database
Room is the official Android persistence library — annotation-driven, compile-time SQL verification, coroutine + Flow integration out of the box.
PHP
Validate Email (RFC-aware)
Use PHP's built-in FILTER_VALIDATE_EMAIL with the FILTER_FLAG_EMAIL_UNICODE flag for IDN domains, plus a length sanity check. Trust this over hand-rolled regex.
PHP
Convert Timestamp to User Timezone
Convert a stored UTC timestamp into the viewer's timezone for display. Round-trip safe: re-converting to UTC always gives back the original timestamp.
Java
flatMap — Flatten Nested Streams
Map each element to a Stream, then concatenate all of them into one. Used everywhere from "all words from a list of sentences" to "all permissions from a list of roles".
Java
Virtual Threads (Java 21+)
Java 21's virtual threads are millions-of-them cheap — JVM multiplexes them onto a small carrier pool. Replaces async/reactive code for most I/O-bound workloads: just write blocking code that doesn't actually block a kernel thread.
Python
Slugify (unicodedata, zero deps)
Convert any string to a URL-safe slug using only stdlib. Normalizes Unicode (NFKD), strips combining marks, lowercases, replaces non-alphanumerics with a separator.
Kotlin
Infix Functions
A single-arg method/extension can be called without dot or parens when marked `infix`. Lets you write DSL-style code like `5 shouldBe 5` or `key to value`.
SQL
BETWEEN — Range Filtering
`BETWEEN a AND b` is inclusive on both ends. Cleaner than `col >= a AND col <= b`. For dates, watch for end-of-day vs midnight boundaries.