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Matt McKegg / mutant



Commit ef9e5ab9d31b22070e49efa9d5db1f9b8f20b572

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computed: remove lazy state, instead non-live `get` temporarily goes live

to handle some weird race conditions caused by out of cycle updates
and fix cyclical loop caused by 52a53f6c954527bd2ff1b45d18bbf6679ef83038
Matt McKegg committed on 6/14/2017, 7:05:03 AM
Parent: 4785d5ea1d640ca8bd46c416557dde4dea903fc7

Files changed

computed.jschanged
test/computed.jsadded
computed.jsView
@@ -32,9 +32,8 @@
3232 … this.outputValue = null
3333 … this.inner = null
3434 … this.updating = false
3535 … this.live = false
36- this.lazy = false
3736 … this.initialized = false
3837 … this.listeners = []
3938 … this.observables = observables
4039 … this.lambda = lambda
@@ -46,8 +45,9 @@
4645 …
4746 … this.context = opts && opts.context || {}
4847 … this.boundOnUpdate = this.onUpdate.bind(this)
4948 … this.boundUpdateNow = this.updateNow.bind(this)
49 …+ this.boundUnlisten = this.unlisten.bind(this)
5050 … }
5151 …
5252 … ProtoComputed.prototype = {
5353 … MutantComputed: function (listener) {
@@ -85,9 +85,9 @@
8585 … if (this.inner) {
8686 … this.releaseInner = this.inner(this.onInnerUpdate.bind(this, this.inner))
8787 … }
8888 … this.live = true
89- this.lazy = true
89 …+ this.update()
9090 …
9191 … if (this.opts && this.opts.onListen) {
9292 … var release = this.opts.onListen()
9393 … if (typeof release === 'function') {
@@ -96,9 +96,9 @@
9696 … }
9797 … }
9898 … },
9999 … unlisten: function () {
100- if (this.live) {
100 …+ if (this.live && !this.listeners.length) {
101101 … this.live = false
102102 …
103103 … if (this.releaseInner) {
104104 … this.releaseInner()
@@ -184,21 +184,13 @@
184184 … this.broadcast()
185185 … }
186186 … },
187187 … getValue: function () {
188- var wasLazy = this.live && this.lazy
189- if (!this.live || this.lazy || this.updating) {
190- this.lazy = false
191- if (this.opts && this.opts.nextTick && this.live && this.lazy) {
192- this.onUpdate() // use cached value to make more responsive
193- } else {
194- if (this.update() && wasLazy) {
195- this.broadcast()
196- }
197- }
198- if (this.inner) {
199- this.outputValue = resolve(this.inner)
200- }
188 …+ if (!this.updating && !this.live) {
189 …+ // temporarily become live to watch for changes until next cycle to stop
190 …+ // potential double refresh and handle weird race conditions
191 …+ this.listen() // triggers update
192 …+ setImmediate(this.boundUnlisten) // only runs if no listeners have been added
201193 … }
202194 … return this.outputValue
203195 … },
204196 … broadcast: function () {
@@ -211,20 +203,18 @@
211203 … }
212204 …
213205 … function extendedComputed (observables, update) {
214206 … var live = false
215- var lazy = false
216207 …
217208 … var instance = computed(observables, function () {
218209 … return update()
219210 … }, {
220- onListen: function () { live = lazy = true },
211 …+ onListen: function () { live = true },
221212 … onUnlisten: function () { live = false }
222213 … })
223214 …
224215 … instance.checkUpdated = function () {
225- if (!live || lazy) {
226- lazy = false
216 …+ if (!live) {
227217 … update()
228218 … }
229219 … }
230220 …
test/computed.jsView
@@ -1,0 +1,47 @@
1 …+require('setimmediate')
2 …+var test = require('tape')
3 …+
4 …+var computed = require('../computed')
5 …+var resolve = require('../resolve')
6 …+var Value = require('../value')
7 …+
8 …+test('computed get accessor', function(t) {
9 …+ var value = Value(1)
10 …+ var obs = computed(value, x => x * 100)
11 …+ t.equal(resolve(obs), 100)
12 …+ value.set(2)
13 …+ t.equal(resolve(obs), 200)
14 …+ t.end()
15 …+})
16 …+
17 …+test('computed lazy watch', function(t) {
18 …+ var value = Value(1)
19 …+ var obs = computed(value, x => x * 100)
20 …+ t.equal(resolve(obs), 100)
21 …+
22 …+ var observedValues = []
23 …+ obs(x => observedValues.push(x))
24 …+ value.set(2)
25 …+ t.deepEqual(observedValues, [200])
26 …+
27 …+ t.end()
28 …+})
29 …+
30 …+test('computed lazy watch with `get` race condition', function(t) {
31 …+ var value = Value(1)
32 …+ var final = Value()
33 …+
34 …+ var obs = computed(value, x => x * 100)
35 …+ t.equal(resolve(obs), 100)
36 …+
37 …+ value(x => {
38 …+ resolve(obs) // resolve obs inside of observer
39 …+ })
40 …+
41 …+ obs(final.set)
42 …+
43 …+ value.set(2)
44 …+
45 …+ t.deepEqual(resolve(final), 200)
46 …+ t.end()
47 …+})

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