packages/reffuse/src/ReffuseContext.ts

@@ -0,0 +1,94 @@
+import { Array, Context, Effect, Layer, Runtime } from "effect"
+import * as React from "react"
+import * as ReffuseRuntime from "./ReffuseRuntime.js"
+
+
+export class ReffuseContext<R> {
+    readonly Context = React.createContext<Context.Context<R>>(null!)
+    readonly Provider = makeProvider(this.Context)
+    readonly AsyncProvider = makeAsyncProvider(this.Context)
+
+
+    useContext(): Context.Context<R> {
+        return React.useContext(this.Context)
+    }
+
+    useLayer(): Layer.Layer<R> {
+        const context = this.useContext()
+        return React.useMemo(() => Layer.effectContext(Effect.succeed(context)), [context])
+    }
+}
+
+export type R<T> = T extends ReffuseContext<infer R> ? R : never
+
+
+export type ReactProvider<R> = React.FC<{
+    readonly layer: Layer.Layer<R, unknown>
+    readonly children?: React.ReactNode
+}>
+
+function makeProvider<R>(Context: React.Context<Context.Context<R>>): ReactProvider<R> {
+    return function ReffuseContextReactProvider(props) {
+        const runtime = ReffuseRuntime.useRuntime()
+
+        const value = React.useMemo(() => Effect.context<R>().pipe(
+            Effect.provide(props.layer),
+            Runtime.runSync(runtime),
+        ), [props.layer, runtime])
+
+        return React.createElement(Context, { ...props, value })
+    }
+}
+
+export type AsyncReactProvider<R> = React.FC<{
+    readonly layer: Layer.Layer<R, unknown>
+    readonly fallback?: React.ReactNode
+    readonly children?: React.ReactNode
+}>
+
+function makeAsyncProvider<R>(Context: React.Context<Context.Context<R>>): AsyncReactProvider<R> {
+    function Inner({ promise, children }: {
+        readonly promise: Promise<Context.Context<R>>
+        readonly children?: React.ReactNode
+    }) {
+        const value = React.use(promise)
+        return React.createElement(Context, { value, children })
+    }
+
+    return function ReffuseContextAsyncReactProvider(props) {
+        const runtime = ReffuseRuntime.useRuntime()
+
+        const promise = React.useMemo(() => Effect.context<R>().pipe(
+            Effect.provide(props.layer),
+            Runtime.runPromise(runtime),
+        ), [props.layer, runtime])
+
+        const inner = React.createElement(Inner, { ...props, promise })
+        return React.createElement(React.Suspense, { children: inner, fallback: props.fallback })
+    }
+}
+
+
+export function make<R = never>() {
+    return new ReffuseContext<R>()
+}
+
+export function useMergeAll<T extends Array<unknown>>(
+    ...contexts: [...{ [K in keyof T]: ReffuseContext<T[K]> }]
+): Context.Context<T[number]> {
+    const values = contexts.map(v => React.use(v.Context))
+    return React.useMemo(() => Context.mergeAll(...values), values)
+}
+
+export function useMergeAllLayers<T extends Array<unknown>>(
+    ...contexts: [...{ [K in keyof T]: ReffuseContext<T[K]> }]
+): Layer.Layer<T[number]> {
+    const values = contexts.map(v => React.use(v.Context))
+
+    return React.useMemo(() => Array.isNonEmptyArray(values)
+        ? Layer.mergeAll(
+            ...Array.map(values, context => Layer.effectContext(Effect.succeed(context)))
+        )
+        : Layer.empty as Layer.Layer<T[number]>,
+    values)
+}