Implementation guides
Practical guides for reference data and developer workflows
Practical checks for phone, ID-format, and locale references, plus JSON, JWT, URL, time, password, and Open Graph workflows.
Reference data
Phone number formatting for test data
Use country format references safely without generating callable test phone numbers.
Use ID format references safely
Why a public ID-format reference is not an identity validator or generator.
Language and locale codes by country
Choose BCP 47 locale tags without confusing language, territory, and script.
Developer workflows
CSV to JSON: preserve text and fix ambiguous rows
Keep leading zeros and long identifiers intact, understand CSV quoting, and resolve duplicate headers, missing cells and UTF-8 errors before converting.
CSS box-shadow: layers, inset shadows and clipping
Understand box-shadow layer order, negative spread, inset rendering and overflow clipping before using generated CSS in your interface.
CSS gradient stops, hard edges and text contrast
Read linear and radial gradient stops correctly, create intentional hard edges, and check text contrast in the rendered layout.
Flexbox sizing, wrapping and source order
Understand Flexbox axes, item sizing and wrapping before copying a generated layout into your project.
CSS Grid areas: visual layout, tracks and source order
Build rectangular grid-template-areas, understand track sizing, and check HTML reading order before using generated CSS.
CSS easing: control points, overshoot and reduced motion
Read cubic-bezier() coordinates, compare easing at the same duration, and respect reduced-motion preferences in the component you ship.
Fluid typography with CSS clamp(): formula and accessibility
Check fluid font-size endpoints, root rem assumptions, browser support and 200% text resizing before shipping clamp() CSS.
XML formatting: well-formedness, whitespace and validation
Understand what an XML syntax check proves, why whitespace can matter, and when to use an XSD validator instead.
Turn JSON into TypeScript without trusting the sample
Use a JSON sample to start a TypeScript contract while keeping runtime checks separate.
Inspect JWT claims without treating them as proof
Read JWT metadata locally for debugging while keeping signature verification and authorization separate.
URL encoding: encode data, not the whole address
Inspect URL components locally and avoid double-encoding query values or paths.
Convert timestamps without losing the time zone
Preserve an instant, name the source time zone, and handle daylight-saving gaps explicitly.
Generate passwords locally, then protect them properly
Use unique random passwords and keep generation separate from storage, recovery, and server-side hashing.
Validate Open Graph metadata before sharing a page
Build escaped social metadata locally and check that canonical URLs, titles, and descriptions tell one story.
Read a text diff without mistaking noise for change
Compare two text revisions locally, handle whitespace deliberately, and know when a diff is not enough.
Cronie schedules: day fields, DST, and step values
Read a five-field Cronie schedule without confusing it with other cron dialects or deployment proof.
WCAG color contrast: read ratios without overclaiming
Apply WCAG 2.2 text and non-text contrast thresholds, understand large text, and know what a two-color ratio cannot prove.
HTML escaping: encode for the destination context
Encode HTML text and quoted attributes without confusing character references with sanitization, JavaScript, CSS, or URL safety.
Unix file permissions: read chmod modes without guessing
Convert Unix permission modes, distinguish files from directories, and review special bits without treating a calculator as an access decision.