From 382efc6f8453fc364730141563738eaaf31880e8 Mon Sep 17 00:00:00 2001
From: Seyyed Morteza Moosavi <smmoosavi@users.noreply.github.com>
Date: Fri, 11 Dec 2020 12:45:31 +0330
Subject: [PATCH] feat(state-wire): support rewiring (#28)

* feat(state-wire): support rewiring

* feat(use-wire-value): support rewiring
---
 src/state-wire/use-state-wire.ts      | 33 +++++++----
 src/state-wire/use-wire-state.test.ts | 85 +++++++++++++++++++++++++++
 src/state-wire/use-wire-state.ts      |  2 -
 src/state-wire/use-wire-value.test.ts | 55 +++++++++++++++++
 src/state-wire/use-wire-value.ts      |  2 -
 5 files changed, 162 insertions(+), 15 deletions(-)

diff --git a/src/state-wire/use-state-wire.ts b/src/state-wire/use-state-wire.ts
index acb923b..7e99ec2 100644
--- a/src/state-wire/use-state-wire.ts
+++ b/src/state-wire/use-state-wire.ts
@@ -1,9 +1,23 @@
-import { useEffect, useState } from 'react';
+import { useEffect, useRef, useState } from 'react';
 import { InitializerOrValue, isInitializer } from '../utils/is-initializer';
 import { isDefined } from '../utils/type-utils';
 import { createStateWire } from './create-state-wire';
 import { StateWire } from './state-wire';
 
+const create = <V>(
+  upLink: StateWire<V | undefined> | null | undefined,
+  initialValue: InitializerOrValue<V | undefined>,
+) => {
+  return createStateWire<V>(
+    upLink || {},
+    isDefined(initialValue)
+      ? isInitializer<V | undefined>(initialValue)
+        ? initialValue()
+        : initialValue
+      : undefined,
+  );
+};
+
 export function useStateWire<V>(upLink: StateWire<V>): StateWire<V>;
 export function useStateWire<V>(
   upLink: StateWire<V | undefined> | null | undefined,
@@ -17,16 +31,13 @@ export function useStateWire<V>(
   upLink: StateWire<V | undefined> | null | undefined,
   initialValue?: InitializerOrValue<V | undefined>,
 ): StateWire<V | undefined> | StateWire<V> {
-  const [[wire, connect]] = useState(() => {
-    return createStateWire<V>(
-      upLink || {},
-      isDefined(initialValue)
-        ? isInitializer<V | undefined>(initialValue)
-          ? initialValue()
-          : initialValue
-        : undefined,
-    );
-  });
+  const [[wire, connect], set] = useState(() => create(upLink, initialValue));
+  const lastUpLinkRef = useRef(upLink);
+
+  if (lastUpLinkRef.current !== upLink) {
+    lastUpLinkRef.current = upLink;
+    set(create(upLink, wire.getValue()));
+  }
   useEffect(() => {
     return connect();
   }, [connect]);
diff --git a/src/state-wire/use-wire-state.test.ts b/src/state-wire/use-wire-state.test.ts
index faf18d9..ba5e65a 100644
--- a/src/state-wire/use-wire-state.test.ts
+++ b/src/state-wire/use-wire-state.test.ts
@@ -287,4 +287,89 @@ describe('useWireState', () => {
       expect(result.current.value2).toBe(wireValue);
     });
   });
+
+  describe('when up-link wire changed', () => {
+    it('should return the new wire value', () => {
+      const { result, rerender } = renderHook(
+        ({ firstWire }: { firstWire: boolean }) => {
+          const wire1 = useStateWire(null, 5);
+          const wire2 = useStateWire(null, 6);
+          const [value] = useWireState(firstWire ? wire1 : wire2);
+          return { value };
+        },
+        { initialProps: { firstWire: true } },
+      );
+      rerender({ firstWire: false });
+      expect(result.current.value).toBe(6);
+    });
+    it('should return update the new wire value if it is undefined', () => {
+      const { result, rerender } = renderHook(
+        ({ firstWire }: { firstWire: boolean }) => {
+          const wire1 = useStateWire<number | undefined>(null, 5);
+          const wire2 = useStateWire<number | undefined>(null, undefined);
+          useWireState(firstWire ? wire1 : wire2);
+          return { wire2 };
+        },
+        { initialProps: { firstWire: true } },
+      );
+      rerender({ firstWire: false });
+
+      expect(result.current.wire2.getValue()).toBe(5);
+    });
+
+    it('should be updated with the new wire', () => {
+      const { result, rerender } = renderHook(
+        ({ firstWire }: { firstWire: boolean }) => {
+          const wire1 = useStateWire(null, 5);
+          const wire2 = useStateWire(null, 6);
+          const [value] = useWireState(firstWire ? wire1 : wire2);
+          return { value, wire1, wire2 };
+        },
+        { initialProps: { firstWire: true } },
+      );
+      rerender({ firstWire: false });
+      act(() => {
+        result.current.wire2.setValue(7);
+      });
+      expect(result.current.value).toBe(7);
+      expect(result.current.wire1.getValue()).toBe(5);
+    });
+
+    it('should not be updated with the old wire', () => {
+      const { result, rerender } = renderHook(
+        ({ firstWire }: { firstWire: boolean }) => {
+          const wire1 = useStateWire(null, 5);
+          const wire2 = useStateWire(null, 6);
+          const [value] = useWireState(firstWire ? wire1 : wire2);
+          return { value, wire1, wire2 };
+        },
+        { initialProps: { firstWire: true } },
+      );
+      rerender({ firstWire: false });
+      act(() => {
+        result.current.wire1.setValue(7);
+      });
+      expect(result.current.value).toBe(6);
+      expect(result.current.wire2.getValue()).toBe(6);
+    });
+
+    it('should only updated the new wire', () => {
+      const { result, rerender } = renderHook(
+        ({ firstWire }: { firstWire: boolean }) => {
+          const wire1 = useStateWire(null, 5);
+          const wire2 = useStateWire(null, 6);
+          const [value, setValue] = useWireState(firstWire ? wire1 : wire2);
+          return { value, setValue, wire1, wire2 };
+        },
+        { initialProps: { firstWire: true } },
+      );
+      rerender({ firstWire: false });
+      act(() => {
+        result.current.setValue(7);
+      });
+      expect(result.current.value).toBe(7);
+      expect(result.current.wire1.getValue()).toBe(5);
+      expect(result.current.wire2.getValue()).toBe(7);
+    });
+  });
 });
diff --git a/src/state-wire/use-wire-state.ts b/src/state-wire/use-wire-state.ts
index a0768f2..214d1ff 100644
--- a/src/state-wire/use-wire-state.ts
+++ b/src/state-wire/use-wire-state.ts
@@ -9,7 +9,6 @@ import {
 import { InitializerOrValue } from '../utils/is-initializer';
 import { isSetStateAction } from '../utils/is-set-state-action';
 import { Defined, isDefined } from '../utils/type-utils';
-import { useStabilityGuard } from '../utils/use-stability-guard';
 import { StateWire } from './state-wire';
 import { useStateWire } from './use-state-wire';
 
@@ -32,7 +31,6 @@ export function useWireState<V>(
   wire: StateWire<V | undefined> | null | undefined,
   initialValue?: InitializerOrValue<V | undefined>,
 ): valueAndAction<V | undefined> | valueAndAction<V> {
-  useStabilityGuard(wire);
   const innerWire = useStateWire(wire, initialValue);
   const valueToReturn = innerWire.getValue();
   const [stateValue, setStateValue] = useState(() => innerWire.getValue());
diff --git a/src/state-wire/use-wire-value.test.ts b/src/state-wire/use-wire-value.test.ts
index 9d6a9ba..ba6d91b 100644
--- a/src/state-wire/use-wire-value.test.ts
+++ b/src/state-wire/use-wire-value.test.ts
@@ -82,4 +82,59 @@ describe('useWireValue', () => {
       expect(result.current.value).toBe(6);
     });
   });
+  describe('when wire changed', () => {
+    it('should use the new wire value', () => {
+      const { result, rerender } = renderHook(
+        ({ firstWire }: { firstWire: boolean }) => {
+          const wire1 = useStateWire(null, 5);
+          const wire2 = useStateWire(null, 6);
+          const value = useWireValue(firstWire ? wire1 : wire2);
+          return { value, wire1, wire2 };
+        },
+        { initialProps: { firstWire: true } },
+      );
+      rerender({ firstWire: false });
+      expect(result.current.value).toBe(6);
+      expect(result.current.wire1.getValue()).toBe(5);
+      expect(result.current.wire2.getValue()).toBe(6);
+    });
+    it('should updated when new wire changed', () => {
+      const { result, rerender } = renderHook(
+        ({ firstWire }: { firstWire: boolean }) => {
+          const wire1 = useStateWire(null, 5);
+          const wire2 = useStateWire(null, 6);
+          const value = useWireValue(firstWire ? wire1 : wire2);
+          return { value, wire1, wire2 };
+        },
+        { initialProps: { firstWire: true } },
+      );
+      rerender({ firstWire: false });
+
+      act(() => {
+        result.current.wire2.setValue(7);
+      });
+      expect(result.current.value).toBe(7);
+      expect(result.current.wire1.getValue()).toBe(5);
+      expect(result.current.wire2.getValue()).toBe(7);
+    });
+    it('should not updated when old wire changed', () => {
+      const { result, rerender } = renderHook(
+        ({ firstWire }: { firstWire: boolean }) => {
+          const wire1 = useStateWire(null, 5);
+          const wire2 = useStateWire(null, 6);
+          const value = useWireValue(firstWire ? wire1 : wire2);
+          return { value, wire1, wire2 };
+        },
+        { initialProps: { firstWire: true } },
+      );
+      rerender({ firstWire: false });
+
+      act(() => {
+        result.current.wire1.setValue(7);
+      });
+      expect(result.current.value).toBe(6);
+      expect(result.current.wire1.getValue()).toBe(7);
+      expect(result.current.wire2.getValue()).toBe(6);
+    });
+  });
 });
diff --git a/src/state-wire/use-wire-value.ts b/src/state-wire/use-wire-value.ts
index fed606a..bab7cc0 100644
--- a/src/state-wire/use-wire-value.ts
+++ b/src/state-wire/use-wire-value.ts
@@ -1,6 +1,5 @@
 import { useDebugValue, useEffect, useState } from 'react';
 import { Defined } from '../utils/type-utils';
-import { useStabilityGuard } from '../utils/use-stability-guard';
 import { ReadonlyStateWire, WireState } from './readonly-state-wire';
 
 export function useWireValue(
@@ -27,7 +26,6 @@ export function useWireValue<W extends ReadonlyStateWire<any>>(
   defaultValue?: WireState<W>,
 ): WireState<W> | undefined {
   type Value = WireState<W>;
-  useStabilityGuard(wire);
   const wireValue = wire?.getValue();
   const valueToReturn = wireValue === undefined ? defaultValue : wireValue;
   useDebugValue(valueToReturn);