Commit 5dfdb498b7d97dce1f07169d43146aa777dd3431
computed: bypass broadcast by returning computed.NO_CHANGE
Matt McKegg committed on 7/20/2016, 4:08:58 AMParent: 2225e7077f112ee10318157443adbbdb5748a50e
Files changed
| computed.js | changed |
| computed.js | |||
|---|---|---|---|
| @@ -1,15 +1,18 @@ | |||
| 1 | 1 … | /* A lazy binding take on computed */ | |
| 2 | 2 … | // - doesn't start watching observables until itself is watched, and then releases if unwatched | |
| 3 | 3 … | // - avoids memory/watcher leakage | |
| 4 | 4 … | // - attaches to inner observables if these are returned from value | |
| 5 | -// - doesn't broadcast if value is same as last value (and is `value type` or observable, can't make assuptions about reference types) | ||
| 5 … | +// - doesn't broadcast if value is same as last value (and is `value type` or observable - can't make assuptions about reference types) | ||
| 6 … | +// - doesn't broadcast if value is computed.NO_CHANGE | ||
| 6 | 7 … | ||
| 7 | 8 … | var resolve = require('./resolve') | |
| 8 | 9 … | var isObservable = require('./is-observable') | |
| 9 | 10 … | ||
| 10 | 11 … | module.exports = computed | |
| 11 | 12 … | ||
| 13 … | +computed.NO_CHANGE = {} | ||
| 14 … | + | ||
| 12 | 15 … | function computed (observables, lambda) { | |
| 13 | 16 … | if (!Array.isArray(observables)) { | |
| 14 | 17 … | observables = [observables] | |
| 15 | 18 … | } | |
| @@ -97,8 +100,13 @@ | |||
| 97 | 100 … | ||
| 98 | 101 … | if (changed || !initialized) { | |
| 99 | 102 … | initialized = true | |
| 100 | 103 … | var newComputedValue = lambda.apply(null, values) | |
| 104 … | + | ||
| 105 … | + if (newComputedValue === computed.NO_CHANGE) { | ||
| 106 … | + return false | ||
| 107 … | + } | ||
| 108 … | + | ||
| 101 | 109 … | if (newComputedValue !== computedValue || (isReferenceType(newComputedValue) && !isObservable(newComputedValue))) { | |
| 102 | 110 … | if (releaseInner) { | |
| 103 | 111 … | releaseInner() | |
| 104 | 112 … | inner = releaseInner = null | |
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