From d9544fde0f5e6a35faa049fdeecd4c8f8650babe Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?V=C3=ADctor=20Oliva?= <olivarra1@gmail.com>
Date: Wed, 19 Oct 2022 17:51:45 +0200
Subject: [PATCH] feat: create-signal

---
 packages/context-state/src/create-signal.ts   | 52 +++++++++++++++++++
 .../src/internal/detached-node.ts             | 12 +++--
 packages/context-state/src/internal/index.ts  |  1 +
 packages/context-state/src/types.ts           |  7 ++-
 4 files changed, 67 insertions(+), 5 deletions(-)
 create mode 100644 packages/context-state/src/create-signal.ts

diff --git a/packages/context-state/src/create-signal.ts b/packages/context-state/src/create-signal.ts
new file mode 100644
index 0000000..4f7f0a2
--- /dev/null
+++ b/packages/context-state/src/create-signal.ts
@@ -0,0 +1,52 @@
+import { Subject } from "rxjs"
+import {
+  getInternals,
+  inactiveContext,
+  NestedMap,
+  recursiveError,
+} from "./internal"
+import type { Signal, StateNode, StringRecord } from "./types"
+
+export const createSignal = <T, K extends StringRecord<any>>(
+  parent: StateNode<any, K>,
+): Signal<T, K> => {
+  const instances = new NestedMap<any[], Subject<T>>()
+  const parentInternals = getInternals(parent)
+
+  parentInternals.childRunners.push((key, isActive) => {
+    const current = instances.get(key)
+    if (isActive && !current) {
+      instances.set(key, new Subject())
+    }
+    if (!isActive && current) {
+      instances.delete(key)
+      current.complete()
+    }
+  })
+
+  return {
+    getSignal$(keyObj: K = {} as K) {
+      const sortedKey = parentInternals.keysOrder.map((key) => keyObj[key])
+      const instance = instances.get(sortedKey)
+      if (!instance)
+        throw (
+          recursiveError(sortedKey, parentInternals, new Set()) ||
+          inactiveContext()
+        )
+      return instance
+    },
+    push(keyOrValue: T | K, value?: T) {
+      const keyObj = (arguments.length > 1 ? keyOrValue : {}) as K
+      const safeValue = arguments.length > 1 ? value! : (keyOrValue as T)
+
+      const sortedKey = parentInternals.keysOrder.map((key) => keyObj[key])
+      const instance = instances.get(sortedKey)
+      if (!instance)
+        throw (
+          recursiveError(sortedKey, parentInternals, new Set()) ||
+          inactiveContext()
+        )
+      instance.next(safeValue)
+    },
+  }
+}
diff --git a/packages/context-state/src/internal/detached-node.ts b/packages/context-state/src/internal/detached-node.ts
index 1b66ff8..3ff9187 100644
--- a/packages/context-state/src/internal/detached-node.ts
+++ b/packages/context-state/src/internal/detached-node.ts
@@ -1,5 +1,5 @@
 import { Observable, ReplaySubject, Subscription } from "rxjs"
-import type { CtxFn, StateNode, StringRecord } from "../types"
+import type { CtxFn, Signal, StateNode, StringRecord } from "../types"
 import {
   InternalStateNode,
   EMPTY_VALUE,
@@ -13,7 +13,7 @@ import {
 } from "./"
 import { NestedMap } from "./nested-map"
 
-const recursiveError = (
+export const recursiveError = (
   key: any[],
   start: InternalStateNode<any, any>,
   searched: Set<InternalStateNode<any, any>>,
@@ -153,9 +153,13 @@ export const detachedNode = <T, K extends StringRecord<any>>(
       }
 
       const ctxObservable = <V, CK extends StringRecord<any>>(
-        node: StateNode<V, any>,
+        node: StateNode<V, CK> | Signal<V, CK>,
         partialKey: Omit<CK, keyof K>,
-      ): Observable<V> => node.getState$({ ...objKey, ...partialKey })
+      ): Observable<V> =>
+        ("getSignal$" in node ? node.getSignal$ : node.getState$)({
+          ...objKey,
+          ...partialKey,
+        } as CK)
 
       const onError = (err: any) => {
         const prevPromise = actualInstance.promise
diff --git a/packages/context-state/src/internal/index.ts b/packages/context-state/src/internal/index.ts
index ab0d722..111a79f 100644
--- a/packages/context-state/src/internal/index.ts
+++ b/packages/context-state/src/internal/index.ts
@@ -4,3 +4,4 @@ export * from "./promisses"
 export * from "./internals"
 export * from "./detached-node"
 export * from "./record-utils"
+export * from "./nested-map"
diff --git a/packages/context-state/src/types.ts b/packages/context-state/src/types.ts
index 69341f0..d18e55b 100644
--- a/packages/context-state/src/types.ts
+++ b/packages/context-state/src/types.ts
@@ -12,10 +12,15 @@ export interface StateNode<T, K extends StringRecord<any>> {
     : (key: K) => Observable<T>
 }
 
+export interface Signal<T, K extends StringRecord<any>> {
+  push: {} extends K ? (value: T) => void : (key: K, value: T) => void
+  getSignal$: {} extends K ? () => Observable<T> : (key: K) => Observable<T>
+}
+
 export type CtxFn<T, K extends StringRecord<any>> = (
   ctxValue: <CT>(node: StateNode<CT, any>) => CT,
   ctxObservable: <CT, CK extends StringRecord<any>>(
-    node: StateNode<CT, any>,
+    node: StateNode<CT, CK> | Signal<CT, CK>,
     key: Omit<CK, keyof K>,
   ) => Observable<CT>,
   key: K,