Commit 2244524e466413910788cad98baa61df4f340866
computed: resolve and broadcast inner value if observable
Matt McKegg committed on 7/15/2016, 3:04:19 AMParent: ec39f72902c3a64aa9841e339bd53cf60182953c
Files changed
| computed.js | changed |
| computed.js | ||
|---|---|---|
| @@ -1,18 +1,30 @@ | ||
| 1 | 1 … | /* A lazy binding take on computed */ |
| 2 | -// doesn't start watching observables until itself is watched, and then releases if unwatched | |
| 3 | -// avoids memory/watcher leakage | |
| 2 … | +// - doesn't start watching observables until itself is watched, and then releases if unwatched | |
| 3 … | +// - avoids memory/watcher leakage | |
| 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) | |
| 4 | 6 … | |
| 5 | 7 … | var resolve = require('./resolve') |
| 8 … | +var isObservable = require('./is-observable') | |
| 6 | 9 … | |
| 7 | 10 … | module.exports = computed |
| 8 | 11 … | |
| 9 | 12 … | function computed (observables, lambda) { |
| 13 … | + if (!Array.isArray(observables)) { | |
| 14 … | + observables = [observables] | |
| 15 … | + } | |
| 16 … | + | |
| 10 | 17 … | var values = [] |
| 11 | 18 … | var releases = [] |
| 12 | 19 … | var computedValue = null |
| 20 … | + | |
| 21 … | + var inner = null | |
| 22 … | + var releaseInner = null | |
| 23 … | + | |
| 13 | 24 … | var live = false |
| 14 | 25 … | var lazy = false |
| 26 … | + var initialized = false | |
| 15 | 27 … | var listeners = [] |
| 16 | 28 … | |
| 17 | 29 … | var result = function (listener) { |
| 18 | 30 … | if (!listener) { |
| @@ -49,16 +61,25 @@ | ||
| 49 | 61 … | if (typeof observables[i] === 'function') { |
| 50 | 62 … | releases.push(observables[i](onUpdate)) |
| 51 | 63 … | } |
| 52 | 64 … | } |
| 65 … | + if (inner) { | |
| 66 … | + releaseInner = inner(onInnerUpdate) | |
| 67 … | + } | |
| 53 | 68 … | live = true |
| 54 | 69 … | lazy = true |
| 55 | 70 … | } |
| 56 | 71 … | } |
| 57 | 72 … | |
| 58 | 73 … | function unlisten () { |
| 59 | 74 … | if (live) { |
| 60 | 75 … | live = false |
| 76 … | + | |
| 77 … | + if (releaseInner) { | |
| 78 … | + releaseInner() | |
| 79 … | + releaseInner = null | |
| 80 … | + } | |
| 81 … | + | |
| 61 | 82 … | while (releases.length) { |
| 62 | 83 … | releases.pop()() |
| 63 | 84 … | } |
| 64 | 85 … | } |
| @@ -73,18 +94,42 @@ | ||
| 73 | 94 … | values[i] = newValue |
| 74 | 95 … | } |
| 75 | 96 … | } |
| 76 | 97 … | |
| 77 | - if (changed) { | |
| 98 … | + if (changed || !initialized) { | |
| 99 … | + initialized = true | |
| 78 | 100 … | var newComputedValue = lambda.apply(null, values) |
| 79 | - if (newComputedValue !== computedValue || typeof newComputedValue === 'object') { | |
| 80 | - computedValue = newComputedValue | |
| 101 … | + if (newComputedValue !== computedValue || (typeof newComputedValue === 'object' && !isObservable(newComputedValue))) { | |
| 102 … | + if (releaseInner) { | |
| 103 … | + releaseInner() | |
| 104 … | + inner = releaseInner = null | |
| 105 … | + } | |
| 106 … | + | |
| 107 … | + if (isObservable(newComputedValue)) { | |
| 108 … | + // handle returning observable from computed | |
| 109 … | + computedValue = newComputedValue() | |
| 110 … | + inner = newComputedValue | |
| 111 … | + if (live) { | |
| 112 … | + releaseInner = inner(onInnerUpdate) | |
| 113 … | + } | |
| 114 … | + } else { | |
| 115 … | + computedValue = newComputedValue | |
| 116 … | + } | |
| 81 | 117 … | return true |
| 82 | 118 … | } |
| 83 | 119 … | } |
| 84 | 120 … | return false |
| 85 | 121 … | } |
| 86 | 122 … | |
| 123 … | + function onInnerUpdate (value) { | |
| 124 … | + if (value !== computedValue || typeof newComputedValue === 'object') { | |
| 125 … | + computedValue = value | |
| 126 … | + for (var i = 0, len = listeners.length; i < len; i++) { | |
| 127 … | + listeners[i](computedValue) | |
| 128 … | + } | |
| 129 … | + } | |
| 130 … | + } | |
| 131 … | + | |
| 87 | 132 … | function onUpdate () { |
| 88 | 133 … | if (update()) { |
| 89 | 134 … | for (var i = 0, len = listeners.length; i < len; i++) { |
| 90 | 135 … | listeners[i](computedValue) |
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