Define typed, module-scoped state and wrap useUrlState in a feature-scoped custom hook so unrelated React components share the same URL-synced state. Covers drawer/modal open-state, tab switching, multi-select toggles, reset/defaults semantics, and the object-identity-based sharing model. Load this skill when storing filters, tabs, drawers, selections, paginators, or any UI state that should survive reloads and be shareable by URL.
Use the URL as a form draft store by pairing useUrlState with react-hook-form (or formik). Share one module-scoped defaults object between both libraries; hydrate useForm.defaultValues from urlState; push form changes back into setUrl via RHF subscribe() (NOT watch()). Load this skill when a form should round-trip its values through the URL — filter forms, search forms, multi-step wizards with shareable draft links.
Reconcile instant local input feedback with URL write throttling. setState updates internal state synchronously (instant re-render); setUrl is throttled and asynchronous (URL catches up on the next tick). Use this skill for text inputs, search boxes, sliders, range pickers, and any control that fires many updates per second where binding setUrl directly to onChange causes perceived lag or wasted URL writes.
SSR-safe useUrlState in Next.js App Router. Forward searchParams from server pages (awaiting the Promise in Next.js 15+), call useSearchParams() in pure client components, decide between useHistory true/false, and use a Proxy (formerly middleware) to expose query params to server layouts. App Router only — Pages Router is not supported. Load this skill for any use of state-in-url/next or anytime URL state must be correct on first paint.
Set up useUrlState for React Router v7 (state-in-url/react-router), React Router v6 (state-in-url/react-router6 — moved here in 6.0.0), and Remix v2 (state-in-url/remix). The hook API is identical across all three; only the import path and per-call NavigateOptions (preventScrollReset, state, replace) differ. Load this skill when wiring useUrlState into any non-Next.js React router or migrating from an older import path.
Use useSharedState (from state-in-url, NOT a framework subpath) as a framework-agnostic cross-component state primitive when URL sync is explicitly NOT wanted. Same module-scoped default-state-identity rule as useUrlState. A lightweight Context.Provider replacement that works in React, Next.js, Vite, Remix without setup. Load this skill when the user wants shared state but specifies "no URL", or for state that is sensitive, ephemeral, or too large to live in the URL.
Use when the user wants to design, redesign, shape, critique, audit, polish, clarify, distill, harden, optimize, adapt, animate, colorize, extract, or otherwise improve a frontend interface. Covers websites, landing pages, dashboards, product UI, app shells, components, forms, settings, onboarding, and empty states. Handles UX review, visual hierarchy, information architecture, cognitive load, accessibility, performance, responsive behavior, theming, anti-patterns, typography, fonts, spacing, layout, alignment, color, motion, micro-interactions, UX copy, error states, edge cases, i18n, and reusable design systems or tokens. Also use for bland designs that need to become bolder or more delightful, loud designs that should become quieter, live browser iteration on UI elements, or ambitious visual effects that should feel technically extraordinary. Not for backend-only or non-UI tasks.
Use when the user wants to design, redesign, shape, critique, audit, polish, clarify, distill, harden, optimize, adapt, animate, colorize, extract, or otherwise improve a frontend interface. Covers websites, landing pages, dashboards, product UI, app shells, components, forms, settings, onboarding, and empty states. Handles UX review, visual hierarchy, information architecture, cognitive load, accessibility, performance, responsive behavior, theming, anti-patterns, typography, fonts, spacing, layout, alignment, color, motion, micro-interactions, UX copy, error states, edge cases, i18n, and reusable design systems or tokens. Also use for bland designs that need to become bolder or more delightful, loud designs that should become quieter, live browser iteration on UI elements, or ambitious visual effects that should feel technically extraordinary. Not for backend-only or non-UI tasks.