FRPtools 1.2.0

- add the ability to have comparators for complex types
- computed.unsubscribeAll() to give more cleanup options

README.md

@@ -46,6 +46,26 @@ it will provide the count of remaining subscriptions.
 ```js
 const unsubscribe = inViewport.subscribe(console.log.bind(console));
 const remainingSubscriptionCount = unsubscribe();
+
+inViewport.unsubscribeAll(); // Call unsubscribeAll to remove child observables/computeds.
+```
+
+### Provide a comparator for complex types
+
+When storing a type that is not determined to be equal with simple equality (===), provide a
+function to determine in the new provided value should be propagated to dependents.
+
+```js
+function setEquals(a, b) {
+	return (
+		a instanceof Set &&
+		b instanceof Set &&
+		[...a].reduce((acc, d) => acc && b.has(d), true) &&
+		[...b].reduce((acc, d) => acc && a.has(d), true)
+	);
+}
+
+const a = observable(new Set([1, 2]), setEquals);
 ```
 
 # [computed](./src/computed.js)
@@ -111,6 +131,33 @@ showDialog.subscribe(console.log.bind(console));
 inViewport(false); // showDialog result recomputed and `false` is written to the console.
 shouldShow(false); // showDialog result recomputed, console.log is not called.
 showDialog(); // showDialog does not recompute, console.log is not called. `false` is returned.
+
+showDialog.detach(); // Call detach to remove this computed from the logic tree.
+showDialog.unsubscribeAll(); // Call unsubscribeAll to remove child observables/computeds.
+```
+
+### Provide a comparator for complex types
+
+When the computed result is a type that is not determined to be equal with simple equality (===),
+provide a function to determine in the new provided value should be propagated to dependents.
+
+```js
+function setEquals(a, b) {
+	return (
+		a instanceof Set &&
+		b instanceof Set &&
+		[...a].reduce((acc, d) => acc && b.has(d), true) &&
+		[...b].reduce((acc, d) => acc && a.has(d), true)
+	);
+}
+
+function _intersection(a, b) {
+	return new Set([...a].filter(x => b.has(x)));
+}
+
+const a = observable(new Set([1, 2]), setEquals);
+const b = observable(new Set([2, 3]), setEquals);
+const intersection = computed(_intersection, [a, b], setEquals);
 ```
 
 # [bundle](./src/bundle.js)

package.json

@@ -1,6 +1,6 @@
 {
 	"name": "frptools",
-	"version": "1.1.0",
+	"version": "1.2.0",
 	"description": "Observable and Computed data streams",
 	"main": "lib/index.js",
 	"jsnext:main": "src/index.js",

spec/computed.spec.js

@@ -155,4 +155,37 @@ describe('computed', () => {
 		expect(b()).toEqual(4);
 		expect(c()).toEqual(7);
 	});
+
+	it('uses a comparator', () => {
+		function setEquals(a, b) {
+			return (
+				a instanceof Set &&
+				b instanceof Set &&
+				[...a].reduce((acc, d) => acc && b.has(d), true) &&
+				[...b].reduce((acc, d) => acc && a.has(d), true)
+			);
+		}
+
+		let runCount = 0;
+
+		function intersection(a, b) {
+			runCount += 1;
+			return new Set([...a].filter(x => b.has(x)));
+		}
+
+		const a = observable(new Set([1, 2]), setEquals);
+		const b = observable(new Set([2, 3]), setEquals);
+		const ABintersection = computed(intersection, [a, b], setEquals);
+
+		expect(runCount).toEqual(0);
+		expect([...ABintersection()]).toEqual([2]);
+		expect(runCount).toEqual(1);
+		b(new Set([3, 2]));
+		expect([...ABintersection()]).toEqual([2]);
+		expect(runCount).toEqual(1);
+		b(new Set([3, 2, 1]));
+		expect(runCount).toEqual(1);
+		expect([...ABintersection()]).toEqual([1, 2]);
+		expect(runCount).toEqual(2);
+	});
 });

spec/observable.spec.js

@@ -61,4 +61,26 @@ describe('observable', () => {
 		expect(a(4)).toEqual(4);
 		expect(runCount).toEqual(3);
 	});
+
+	it('uses a comparator', () => {
+		function setEquals(a, b) {
+			return (
+				a instanceof Set &&
+				b instanceof Set &&
+				[...a].reduce((acc, d) => acc && b.has(d), true) &&
+				[...b].reduce((acc, d) => acc && a.has(d), true)
+			);
+		}
+
+		let runCount = 0;
+
+		const a = observable(new Set([1, 2]), setEquals);
+		a.subscribe(() => (runCount += 1));
+		expect([...a()]).toEqual([1, 2]);
+		expect(runCount).toEqual(0);
+		expect([...a(new Set([2, 1]))]).toEqual([1, 2]);
+		expect(runCount).toEqual(0);
+		expect([...a(new Set([3, 2, 1]))]).toEqual([3, 2, 1]);
+		expect(runCount).toEqual(1);
+	});
 });

src/computed.js

@@ -1,3 +1,5 @@
+import { eq } from './util.js';
+
 export function computed(fn, dependencies = [], comparator = eq) {
 	const subscribers = new Set();
 	const dependents = new Set();
@@ -23,7 +25,7 @@ export function computed(fn, dependencies = [], comparator = eq) {
 		if (isDirty) {
 			const newVal = fn.apply(null, dependencies.map(runParam));
 			isDirty = false;
-			if (!comparator(newVal, val)) {
+			if (!comparator(val, newVal)) {
 				val = newVal;
 				subscribers.forEach(s => s(val));
 			}