solid-js

solid-js is the reactive core. It has no knowledge of the DOM; the same primitives run in the browser, on the server, and in tests. Rendering functions live in @solidjs/web.

Every export here is imported from "solid-js":

import { createSignal, createMemo, createStore, Show, For } from "solid-js";

Reactivity

Values that change over time and the computations that follow them. Reactivity explains the model.

• createSignal creates a readable, writable value.
• createMemo derives a cached value from other reactive reads, including async ones.
• createEffect runs side effects after tracked values change.
• createOptimistic creates a signal whose writes inside an action are tentative.
• isPending reports that a new answer is on the way; latest reads it early.
• untrack reads without subscribing; flush drains the update queue now.

Stores

Nested reactive state with per-property tracking. Stores covers drafts, projections, and optimistic stores.

• createStore wraps an object or array; the setter receives a draft.
• createProjection derives a read-only store from other reactive reads.
• createOptimisticStore is the store form of createOptimistic.
• reconcile merges new data into a store by key.
• merge and omit combine and split props without losing reactivity.

Lifecycle and actions

Coordinating async work and the moments around it. Async reactivity is the concept page.

• action runs a mutation whose writes commit together.
• onSettled runs once after the current owner's pending work has finished, and can return a cleanup.
• refresh re-asks an async source; affects marks values as pending while it does.
• until awaits a reactive condition.

Components and context

• createContext and useContext share a value with a subtree.
• children resolves props.children for inspection.
• lazy code-splits a component.
• createUniqueId generates ids that match between server and client.

Flow components

Built-in components for conditions, lists, and boundaries. Components and JSX and Boundaries show them in use.

• Show renders content when a condition holds.
• Switch and Match pick the first matching branch.
• For renders a row per array item; Repeat renders a row per index.
• Loading shows a fallback while async reads have no value.
• Errored renders a fallback when the subtree throws.
• Reveal orders how sibling Loading boundaries appear.

Advanced

Owner introspection, specialized effects, store internals, list primitives, manual hydration, interop, and development hooks. These pages support libraries and tooling; application code rarely needs them.

• createRoot, getOwner, and runWithOwner manage reactive scopes by hand.
• createRenderEffect and onCleanup serve renderers and custom primitives.
• mapArray and repeat are the list primitives behind For and Repeat.
• isHydrating says whether the running code is claiming server-rendered DOM; isHydratable whether the owner sits where hydration applies.
• DEV exposes the development diagnostics that Debugging reactivity reads.

Types

• Reactive types: Accessor, Setter, Signal
• Store types: Store
• Component types: Component, ParentProps, ValidComponent, and friends
• Context types and Owner
• JSX: JSX.Element and the intrinsic element attributes