From e37679c2c9443f07d923aab3b8a65d6c42bd6f9d Mon Sep 17 00:00:00 2001
From: Timothy Farrell <tim@thecookiejar.me>
Date: Thu, 2 Nov 2017 08:35:52 -0500
Subject: [PATCH] Add computed.unsubscribeAll. Sometimes we want to remove...

...subscribers without removing dependencies.
---
 packages/frptools/src/computed.js | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/packages/frptools/src/computed.js b/packages/frptools/src/computed.js
index a7009ea..679c2c9 100644
--- a/packages/frptools/src/computed.js
+++ b/packages/frptools/src/computed.js
@@ -4,6 +4,7 @@ export function computed(fn, dependencies = [], comparator = eq) {
 	let isDirty = true;
 	let val;
 
+	// Receive dirty flag from parent logic node (dependency).  Pass it down.
 	function _computedDirtyReporter(_, skipPropagation) {
 		if (!isDirty) {
 			isDirty = true;
@@ -17,6 +18,7 @@ export function computed(fn, dependencies = [], comparator = eq) {
 
 	const dependentSubscriptions = Array.from(dependencies).map(d => d._d(_computedDirtyReporter));
 
+	// Compute new value, call subscribers if changed.
 	const accessor = function _computed() {
 		if (isDirty) {
 			const newVal = fn.apply(null, dependencies.map(runParam));
@@ -29,6 +31,7 @@ export function computed(fn, dependencies = [], comparator = eq) {
 		return val;
 	};
 
+	// Add child nodes to the logic graph (value-based)
 	accessor.subscribe = fn => {
 		subscribers.add(fn);
 		return () => {
@@ -37,17 +40,25 @@ export function computed(fn, dependencies = [], comparator = eq) {
 		};
 	};
 
+	// Add child nodes to the logic graph (dirty-based)
 	accessor._d = fn => {
 		dependents.add(fn);
 		return () => dependents.delete(fn);
 	};
 
+	// Remove this node from the logic graph completely
 	accessor.detach = () => {
 		subscribers.clear();
 		dependents.clear();
 		dependentSubscriptions.forEach(runParam);
 	};
 
+	// Remove child nodes from the logic graph
+	accessor.unsubscribeAll = () => {
+		subscribers.clear();
+		dependents.clear();
+	};
+
 	return accessor;
 }