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
HTML
Code Markup — pre, code, kbd, samp, var
HTML has five semantic elements for technical text: `<code>` (source code), `<pre>` (preserve whitespace), `<kbd>` (keyboard input), `<samp>` (sample output), `<var>` (math/program variable). Each has a different meaning to screen readers and search engines.
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Java
Jackson — Basic ObjectMapper
`com.fasterxml.jackson.databind.ObjectMapper` is the JSON standard for Java. Construct once (it's expensive + thread-safe) and reuse for every serialization in your app.
SQL
COALESCE / NULLIF — Null Handling
`COALESCE(a, b, c)` returns the first non-NULL value — perfect for fallbacks. `NULLIF(a, b)` returns NULL when a equals b — handy for "treat sentinel as null".
SQL
IS DISTINCT FROM — Null-Safe Equality
`=` returns NULL when either side is NULL. `IS DISTINCT FROM` (and its inverse `IS NOT DISTINCT FROM`) treat NULLs as equal to themselves — the right tool for change detection.
Kotlin
observable — Listen for Property Changes
`Delegates.observable(initial) { prop, old, new -> ... }` fires a callback every time the property changes. Useful for state-tracking, simple observability without a full reactive lib.
PHP
Simple cURL GET with Timeout
A no-dependency HTTP GET helper with sensible defaults: short timeout, follow redirects, return body as string, throw on transport error. Pass extra headers as a simple associative array.
PHP
Validate Credit Card (Luhn check)
Apply the Luhn checksum algorithm to a credit card number. Strips spaces/dashes first. This validates the format — not whether the card actually exists or has funds.
TypeScript
clamp / lerp / mapRange
Three numeric utilities you reach for constantly in animation, UI math, and audio code. Generic enough to use anywhere, no Math.* dance required.
Bash
Backup File With Timestamp
Keep a versioned copy of a config or log before modifying it. Avoid `cp file file.bak` which overwrites old backups; use a date-stamped name.
Bash
Self-Documenting Help Text
A pattern where comments in your script double as inline help. Grep your own file for a sentinel string and print it as the --help output.
HTML
Modern Meta Tags (viewport, theme-color, etc.)
The non-obvious meta tags that improve mobile rendering, status-bar coloring, and dark-mode behavior in 2025 browsers. Copy this block whole.
HTML
Hero Section
The big "above the fold" intro on a landing page: large heading, sub-copy, primary CTA, optional supporting image. Keep the H1 unique to the page and one per document.
Bash
Unique While Preserving Order
`sort -u` re-orders. `awk '!seen[$0]++'` is the classic order-preserving dedupe — and it's a single line.
TypeScript
Debounce (typed)
Wait until the caller stops invoking for `delay` ms, then call the function with the most recent arguments. The TS version preserves the original signature so the returned function has the same parameters.
Java
Switch Expressions (Java 14+)
`switch` is now also an expression — it returns a value. Use `->` arrows for fall-through-free arms; `yield` inside `{ }` blocks for multi-statement arms. No more accidental forgotten `break`.
Java
ConcurrentHashMap — Thread-Safe Map
The default thread-safe map. Better than `Collections.synchronizedMap` — segmented locking allows multiple readers AND writers. Use `compute`, `merge`, `putIfAbsent` for atomic compound updates.
SQL
LATERAL Join — Per-Row Subquery
PostgreSQL `LATERAL` lets a join's right-hand side reference the left-hand row — like a correlated subquery, but supplying multiple columns or rows. Perfect for "top-N per group".