@praxisjs/shared/internal

import { isSignal, isComponent, flattenChildren } from '@praxisjs/shared/internal'
import type { ComponentConstructor, BaseReactive } from '@praxisjs/shared/internal'

Type guards

Runtime predicates used by the renderer and decorator implementations to narrow unknown values.

isSignal(source)

Returns true if source is a signal created by signal().

function isSignal(source: unknown): boolean

Checks for the __isSignal brand property set internally by signal().

isComputed(source)

Returns true if source is a computed value created by computed().

function isComputed(source: unknown): boolean

Checks for the __isComputed brand property set internally by computed().

isReactive(source)

Returns true if source is either a signal or a computed value.

function isReactive(source: unknown): boolean

Equivalent to isSignal(source) || isComputed(source).

isComponent(source)

Returns true if source is a component constructor decorated with @Component.

function isComponent(source: unknown): source is ComponentConstructor

Checks for the __isComponent brand property set by the @Component decorator.

Utilities

flattenChildren(children, out?)

Recursively flattens a nested children structure into a single flat array. Used by the renderer to normalize JSX children before mounting.

function flattenChildren(children: unknown, out?: unknown[]): unknown[]

flattenChildren([['a', 'b'], ['c']])
// → ['a', 'b', 'c']

Types

BaseReactive<T>

Base interface shared by Signal<T> and Computed<T>. Use this when you need to accept either.

interface BaseReactive<T> {
  (): T
  subscribe(effect: (value: T) => void): () => void
}

ComponentConstructor<P>

Interface that every component class satisfies after being decorated with @Component. Used by the router, DI container, and renderer to accept component types.

interface ComponentConstructor<P = Record<string, unknown>> {
  new(props: P): ComponentInstance
  __isComponent: true
  __isStateless: boolean
  name: string
}

ComponentInstance

Interface for the instance side of a component. Implemented by RootComponent from @praxisjs/core/internal.

interface ComponentInstance {
  _mounted: boolean
  _anchor?: Comment
  _stateDirty?: boolean
  _setProps(p: Record<string, unknown>): void
  render(): Node | Node[] | null
  onBeforeMount?(): void
  onMount?(): void
  onUnmount?(): void
  onError?(e: Error): void
}

ReactiveChildren

Type for arrow-function children in JSX — the mechanism that creates fine-grained DOM subscriptions.

type ReactiveChildren = () =>
  | RenderedValue
  | RenderedValue[]
  | ReactiveChildren[]

When the renderer encounters a ReactiveChildren value, it wraps the call in an effect that updates only that specific DOM node when the result changes.

Cleanup

Alias for a no-argument cleanup function returned by subscriptions and effects.

type Cleanup = () => void