[wip] push nodes impl

packages/signia/src/Computed.ts

@@ -98,6 +98,8 @@ export interface ComputedOptions<Value, Diff> {
 	 * @returns
 	 */
 	isEqual?: (a: any, b: any) => boolean
+
+	isPush?: boolean
 }
 
 /**
@@ -140,6 +142,7 @@ export class _Computed<Value, Diff = unknown> implements Computed<Value, Diff> {
 	}
 
 	historyBuffer?: HistoryBuffer<Diff>
+	isPush: boolean
 
 	// The last-computed value of this signal.
 	private state: Value = UNINITIALIZED as unknown as Value
@@ -167,6 +170,7 @@ export class _Computed<Value, Diff = unknown> implements Computed<Value, Diff> {
 		}
 		this.computeDiff = options?.computeDiff
 		this.isEqual = options?.isEqual ?? null
+		this.isPush = options?.isPush ?? false
 	}
 
 	__unsafe__getWithoutCapture(): Value {

packages/signia/src/__tests__/computed.test.ts

@@ -587,3 +587,24 @@ describe(getComputedInstance, () => {
 		expect(bInst).toBeInstanceOf(_Computed)
 	})
 })
+
+describe('push computeds', () => {
+	it('prevent traversal', () => {
+		const user = atom('', { id: 1, name: 'steve' })
+		const name = computed('', () => user.value.name, { isPush: true })
+		const nameLength = computed('', () => name.value.length)
+		let numNameLengthReactions = 0
+		const r = reactor('', () => {
+			numNameLengthReactions++
+			nameLength.value
+		})
+		r.start()
+		expect(numNameLengthReactions).toBe(1)
+		const lastTraversed = r.scheduler.lastTraversedEpoch
+
+		user.set({ id: 2, name: 'steve' })
+
+		expect(numNameLengthReactions).toBe(1)
+		expect(r.scheduler.lastTraversedEpoch).toBe(lastTraversed)
+	})
+})