From 25d5defdca51b5b138a37a87aee4a4cdfff05bbf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Julien=20Valverd=C3=A9?= <julien.valverde@mailo.com>
Date: Sat, 15 Nov 2025 05:04:34 +0100
Subject: [PATCH] Add Query module

---
 packages/effect-fc/src/Query.ts | 29 +++++++++++++++++++++++++++++
 packages/effect-fc/src/index.ts |  1 +
 2 files changed, 30 insertions(+)
 create mode 100644 packages/effect-fc/src/Query.ts

diff --git a/packages/effect-fc/src/Query.ts b/packages/effect-fc/src/Query.ts
new file mode 100644
index 0000000..8c549b8
--- /dev/null
+++ b/packages/effect-fc/src/Query.ts
@@ -0,0 +1,29 @@
+import { type Effect, Pipeable, Predicate, type Stream } from "effect"
+
+
+export const QueryTypeId: unique symbol = Symbol.for("@effect-fc/Query/Query")
+export type QueryTypeId = typeof QueryTypeId
+
+export interface Query<in out K extends readonly any[], in out A, in out E = never, out R = never, in out P = never>
+extends Pipeable.Pipeable {
+    readonly [QueryTypeId]: QueryTypeId
+
+    readonly key: Stream.Stream<K>
+    readonly query: (key: K) => Effect.Effect<A, E, R>
+    readonly initialProgress: P
+}
+
+class QueryImpl<in out K extends readonly any[], in out A, in out E = never, out R = never, in out P = never>
+extends Pipeable.Class() implements Query<K, A, E, R, P> {
+    readonly [QueryTypeId]: QueryTypeId = QueryTypeId
+
+    constructor(
+        readonly key: Stream.Stream<K>,
+        readonly query: (key: K) => Effect.Effect<A, E, R>,
+        readonly initialProgress: P,
+    ) {
+        super()
+    }
+}
+
+export const isQuery = (u: unknown): u is Query<unknown[], unknown, unknown, unknown, unknown> => Predicate.hasProperty(u, QueryTypeId)
diff --git a/packages/effect-fc/src/index.ts b/packages/effect-fc/src/index.ts
index 08e0b73..18468a4 100644
--- a/packages/effect-fc/src/index.ts
+++ b/packages/effect-fc/src/index.ts
@@ -5,6 +5,7 @@ export * as Form from "./Form.js"
 export * as Memoized from "./Memoized.js"
 export * as PropertyPath from "./PropertyPath.js"
 export * as PubSub from "./PubSub.js"
+export * as Query from "./Query.js"
 export * as ReactRuntime from "./ReactRuntime.js"
 export * as Result from "./Result.js"
 export * as SetStateAction from "./SetStateAction.js"