Support setters

.changeset/hot-ties-play.md

@@ -0,0 +1,5 @@
+---
+"deepsignal": minor
+---
+
+Add support for setters.

packages/deepsignal/core/src/index.ts

@@ -6,6 +6,7 @@ const arrayToArrayOfSignals = new WeakMap();
 const proxies = new WeakSet();
 const objToIterable = new WeakMap();
 const rg = /^\$/;
+const descriptor = Object.getOwnPropertyDescriptor;
 let peeking = false;
 
 export const deepSignal = <T extends object>(obj: T): DeepSignal<T> => {
@@ -58,7 +59,7 @@ const get =
 		const key = returnSignal ? fullKey.replace(rg, "") : fullKey;
 		if (
 			!signals.has(key) &&
-			typeof Object.getOwnPropertyDescriptor(target, key)?.get === "function"
+			typeof descriptor(target, key)?.get === "function"
 		) {
 			signals.set(
 				key,
@@ -83,6 +84,8 @@ const get =
 const objectHandlers = {
 	get: get(false),
 	set(target: object, fullKey: string, val: any, receiver: object): boolean {
+		if (typeof descriptor(target, fullKey)?.set === "function")
+			return Reflect.set(target, fullKey, val, receiver);
 		if (!proxyToSignals.has(receiver)) proxyToSignals.set(receiver, new Map());
 		const signals = proxyToSignals.get(receiver);
 		if (fullKey[0] === "$") {

packages/deepsignal/core/test/index.test.tsx

@@ -189,6 +189,21 @@ describe("deepsignal/core", () => {
 			expect(store.nested.b).to.equal(3);
 		});
 
+		it("should support setting values with setters", () => {
+			const store = deepSignal({
+				counter: 1,
+				get double() {
+					return store.counter * 2;
+				},
+				set double(val) {
+					store.counter = val / 2;
+				},
+			});
+			expect(store.counter).to.equal(1);
+			store.double = 4;
+			expect(store.counter).to.equal(2);
+		});
+
 		it("should update array length", () => {
 			expect(store.array.length).to.equal(2);
 			store.array.push(4);
@@ -394,6 +409,31 @@ describe("deepsignal/core", () => {
 	});
 
 	describe("computations", () => {
+		it("should subscribe to values mutated with setters", () => {
+			const store = deepSignal({
+				counter: 1,
+				get double() {
+					return store.counter * 2;
+				},
+				set double(val) {
+					store.counter = val / 2;
+				},
+			});
+			let counter = 0;
+			let double = 0;
+
+			effect(() => {
+				counter = store.counter;
+				double = store.double;
+			});
+
+			expect(counter).to.equal(1);
+			expect(double).to.equal(2);
+			store.double = 4;
+			expect(counter).to.equal(2);
+			expect(double).to.equal(4);
+		});
+
 		it("should subscribe to changes when an item is removed from the array", () => {
 			const store = deepSignal([0, 0, 0]);
 			let sum = 0;