References

Essential Git commands with explanations, examples, and quick copy.

Complete reference for CSS properties with browser compatibility notes.

Quick reference for regular expression syntax, flags, and patterns.

Complete reference for HTTP request and response headers.

Modern JavaScript ES6+ syntax reference — destructuring, async/await, arrays, classes, and more.

TypeScript reference covering types, generics, utility types, and type guards.

Python 3 reference — comprehensions, decorators, error handling, and modern syntax.

Go language reference — structs, interfaces, goroutines, channels, and generics.

Rust reference — ownership, borrowing, traits, pattern matching, and iterators.

SQL reference — joins, window functions, CTEs, aggregates, and transactions.

Advanced Git reference — interactive rebase, reflog, bisect, worktrees, and submodules.

Quick reference for React hooks, components, props, context, and performance patterns.

App Router reference — routing, data fetching, server actions, middleware, and rendering.

Vue 3 reference — template syntax, Composition API, components, slots, and routing.

Utility class reference for layout, spacing, typography, colors, and responsive design.

Angular reference — components, data binding, directives, services, and RxJS basics.

Express reference — routing, middleware, request/response objects, and error handling.

Django reference — models, migrations, views, URLs, templates, forms, and the ORM.

Flexbox reference — container/item properties, alignment, and common layout patterns.

CSS Grid reference — template columns/rows, placement, alignment, and layout patterns.

Reference for CSS transitions, keyframe animations, timing functions, and common patterns.

HTML5 reference — semantic elements, forms, media, global attributes, and basic APIs.

SVG reference — shapes, path data commands, gradients, transforms, filters, and animation.

Accessibility reference — ARIA roles, states, properties, and common accessible patterns.

SEO reference — meta tags, Open Graph, Twitter Cards, structured data, and Core Web Vitals.

Java syntax, collections, streams, generics, records, and switch expressions at a glance.

C# syntax, LINQ, async/await, records, pattern matching, and nullable reference types.

PHP syntax, arrays, string functions, superglobals, OOP, and modern PHP features.

Ruby syntax, blocks/procs/lambdas, arrays/hashes, enumerable methods, and symbols.

Server blocks, location matching, reverse proxy, SSL config, rewrites, and common directives.

Common cmdlets, pipeline operators, variables, control flow, and comparison operators.

Vim/Neovim modes, movement, editing, visual mode, search/replace, registers, and macros.

VS Code keyboard shortcuts for editing, navigation, multi-cursor, search, and debugging.

Common commands for npm, Yarn, and pnpm side by side — install, scripts, workspaces, and more.

systemctl commands, journalctl usage, unit file anatomy, timers, and troubleshooting.

Time and space complexity reference for common data structures and algorithms.

Searchable reference table of all 128 ASCII codes with decimal, hex, octal, binary, and character views.

Searchable reference for npm and Node.js package manager commands, with flags and real examples.

Searchable reference for browser, text editing, window management, VS Code, and terminal keyboard shortcuts on Windows/Linux and Mac.

Searchable, filterable reference for Emmet HTML and CSS abbreviation syntax, with expandable examples showing the generated markup or CSS for each abbreviation.

Searchable reference of common DNS record types (A, AAAA, CNAME, MX, TXT, NS, SOA, PTR, SRV, CAA, and DNSSEC records) with their purpose and a real-world example.

Find out what day of the week any date falls on, plus its day-of-year number, leap year status, and approximate week number.

Find the approximate moon phase for any date using a standard astronomical approximation — new moon, quarters, gibbous, and full moon, with a visual phase indicator.

Find which of the 12 Western zodiac signs a birth date falls under, along with its date range and classical element (Fire, Earth, Air, or Water).

Convert a dog's age into approximate human-equivalent years using the American Veterinary Medical Association's guideline — more accurate than the old "multiply by 7" rule.

Convert shoe sizes between US, UK, EU, and centimeters for men's and women's sizing, using standard published conversion charts.

Reference dimensions for A-series (A0-A7), B-series (B0-B7), and US/ANSI paper sizes (Letter, Legal, Tabloid), shown in millimeters, centimeters, or inches.

Calculate aspect ratio, total megapixels, and pixels-per-inch (PPI) from a screen resolution and physical diagonal size, with common resolution name lookup.

Convert between common cooking volume units (teaspoons, tablespoons, cups, pints, quarts, gallons, mL, liters) or weight units (ounces, pounds, grams, kilograms).

Find your Chinese zodiac animal and element from your birth year, based on the traditional 12-year animal cycle and 10-year elemental cycle.

Convert your dog or cat's age into human-equivalent years using scientifically-informed non-linear formulas, not the oversimplified "×7" myth.

Estimate your ovulation day, fertile window, and next expected period from your last menstrual period date and average cycle length.

Calculate body surface area using the Mosteller and Du Bois formulas from height and weight — commonly used for medication dosing and burn assessment.

Search the periodic table by element name, symbol, or atomic number to instantly find atomic mass, category, and other key facts.

Calculate the minimum recommended copper wire gauge (AWG) for a circuit based on current, run length, voltage, and acceptable voltage drop.

Estimate a child's weight-for-age percentile (0-36 months) compared to WHO reference data, using sex, age in months, and current weight.

Look up the mathematically optimal blackjack action (hit, stand, double, or split) for any hard total, soft total, or pair against any dealer upcard.

Calculate the "feels like" wind chill temperature from air temperature and wind speed using the official U.S. National Weather Service formula.

Convert a finger circumference or ring inner diameter measurement (in mm) into US, UK/AU, and EU ring sizes using a standard sizing reference table.