Code snippets

137 snippets

• TypeScript Tested

  Parse JSON into a typed value with a guard

  Safely turn unknown JSON into a typed result by validating its shape instead of casting.

• Python Tested

  Parse and format ISO 8601 dates in UTC

  Convert ISO timestamps to timezone-aware UTC datetimes and back, avoiding naive datetime bugs.

• Bash

  Parse command-line flags with getopts

  Handle -v, -o FILE and -h in a bash script with getopts and a usage message.

• Bash

  Run commands in parallel with xargs

  Process many files concurrently with xargs -P, safely handling spaces and newlines in names.

• JavaScript Tested

  Run a function only once

  Wrap a function so it executes on the first call and returns the same result afterwards.

• TypeScript Tested

  Non-empty array type

  Encode "at least one element" in the type so head, max and similar functions never see an empty array.

• SQL

  Moving average with a window frame

  Compute a 7-day rolling average with AVG over a ROWS BETWEEN frame.

• CSS

  A small modern CSS reset

  Sensible defaults for box sizing, media, form fonts and text wrapping in a dozen lines.

• JavaScript Tested

  Memoize a function

  Cache results by argument so expensive pure functions only run once per distinct input.

• Python Tested

  Cache function results with functools.lru_cache

  Memoize pure functions with a bounded least-recently-used cache and inspect or clear it.

• Bash

  Timestamped logging functions for scripts

  Small log, warn and die helpers that write ISO timestamps to stderr and keep stdout clean for data.

• HTML

  Lazy load images and iframes natively

  Defer off-screen images and embeds with loading="lazy", while keeping the main image eager to protect LCP.