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
Go
base64 Encode / Decode
`encoding/base64` has Standard, URL-safe, and Raw (no padding) variants. URL-safe replaces `+/` with `-_` so the output is safe in query strings and filenames.
@admin
TypeScript
Branded Types (nominal typing)
TypeScript is structurally typed, so `string` and `string` are interchangeable even when they semantically aren't (UserId vs PostId). The "brand" trick adds a phantom property that exists only at compile time, giving you nominal-ish typing.
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.
Python
Multipart File Upload
POST a file (or several) as multipart/form-data using requests, with optional extra form fields. Lets you upload to /avatar-style endpoints without manual boundary construction.
Go
Graceful HTTP Shutdown
On SIGINT/SIGTERM, stop accepting new connections but let in-flight requests finish. The `http.Server.Shutdown` method does exactly that — with a deadline.
Go
Basic Unit Test with go test
Tests live in `*_test.go` files alongside the code. Functions named `TestXxx(t *testing.T)` are picked up by `go test`. Use `t.Errorf` for soft fails (continues running), `t.Fatalf` for hard fails.
SQL
ROLLUP — Subtotals and Grand Totals
`GROUP BY ROLLUP` adds subtotal rows (with NULL for the rolled-up columns) plus a grand total. Drop into reports without writing UNIONs by hand.
TypeScript
Environment Variable Validator
Validate process.env at boot-time and exit fast if anything's missing. The returned object is typed so the rest of the code reads `env.DATABASE_URL` instead of `process.env.DATABASE_URL!`.
PHP
UTF-8 Safe substr / strlen
Wrap mb_* with sensible defaults so you stop accidentally chopping multi-byte characters in half. Defensive helpers for projects where input is not guaranteed ASCII.
Go
Multiple Return Values + Named Returns
Go functions can return multiple values — most idiomatically a `(result, error)` pair. Named returns let you document the meaning of each value AND enable naked returns in short functions.
PHP
Generate Identicon Avatar
Render a deterministic 5x5 symmetric "identicon" placeholder avatar from any seed (usually a user's email or username). No external service — pure GD.
Java
BufferedReader / BufferedWriter
For large files or line-oriented protocols, wrap a Reader/Writer in `Buffered*`. Reduces per-call overhead from many small reads to fewer large ones. Always close with try-with-resources.
Go
Methods and Receivers
Methods are functions with a receiver argument. Use pointer receivers when you mutate, when the struct is large, OR for consistency (mixing pointer + value receivers on the same type is a common bug source).
JavaScript
UUID v4 Generator
Generates a RFC 4122 compliant version-4 UUID. Uses crypto.randomUUID() in modern environments (Node 14.17+, all modern browsers) and falls back to a Math.random()-based implementation for older runtimes. The fallback is suitable for non-security-critical IDs such as UI element keys and local correlation IDs.
SQL
INNER JOIN — Match Rows in Both Tables
Returns rows where the join condition matches in BOTH tables. The default JOIN. Use table aliases (`u`, `o`) for readability when joining 3+ tables.
Bash
Watch a File for Changes (no inotify dep)
inotifywait is great when available, but on systems without inotify-tools you can poll mtime. Cheap enough to use in dev/CI workflows.
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.