git ssb

1
var Value = require('./value')
2
var LazyWatcher = require('./lib/lazy-watcher')
3
var isSame = require('./lib/is-same')
4
var resolve = require('./resolve')
5
var isObservable = require('./is-observable')
6
var forEachPair = require('./for-each-pair')
7
var addLookupMethods = require('./lib/add-lookup-methods')
8
9
module.exports = Dict
10
11
function Dict (defaultValues, opts) {
12
  var object = Object.create({})
13
  var sources = {}
14
  var objectReleases = {}
15
  var fixedIndexing = opts && opts.fixedIndexing || false
16
17
  var releases = []
18
  var comparer = opts && opts.comparer || null
19
20
  var binder = LazyWatcher(update, listen, unlisten)
21
  binder.value = object
22
23
  if (opts && opts.nextTick) binder.nextTick = true
24
  if (opts && opts.idle) binder.idle = true
25
26
  if (defaultValues) {
27
    forEachPair(defaultValues, put)
28
  }
29
30
  var observable = function MutantDictionary (listener) {
31
    if (!listener) {
32
      return binder.getValue()
33
    }
34
    return binder.addListener(listener)
35
  }
36
37
  addLookupMethods(observable, sources)
38
39
  observable.put = function (key, valueOrObs) {
40
    valueOrObs = getObsValue(valueOrObs)
41
    put(key, valueOrObs)
42
    binder.broadcast()
43
    return valueOrObs
44
  }
45
46
  observable.clear = function () {
47
    Object.keys(sources).forEach(function (key) {
48
      tryInvoke(objectReleases[key])
49
      delete sources[key]
50
      delete objectReleases[key]
51
      delete object[key]
52
    })
53
    binder.broadcast()
54
  }
55
56
  observable.delete = function (key) {
57
    tryInvoke(objectReleases[key])
58
    delete sources[key]
59
    delete objectReleases[key]
60
    delete object[key]
61
    binder.broadcast()
62
  }
63
64
  observable.set = function (values) {
65
    if (fixedIndexing) {
66
      var keys = []
67
68
      forEachPair(values, function (key, value) {
69
        keys.push(key)
70
        if (sources[key]) {
71
          sources[key].set(value)
72
        } else {
73
          put(key, getObsValue(value))
74
        }
75
      })
76
77
      Object.keys(sources).forEach(function (key) {
78
        if (!keys.includes(key)) {
79
          tryInvoke(objectReleases[key])
80
          delete sources[key]
81
          delete objectReleases[key]
82
          delete object[key]
83
        }
84
      })
85
    } else {
86
      Object.keys(sources).forEach(function (key) {
87
        tryInvoke(objectReleases[key])
88
        delete sources[key]
89
        delete objectReleases[key]
90
        delete object[key]
91
      })
92
93
      forEachPair(values, put)
94
      binder.broadcast()
95
    }
96
  }
97
98
  return observable
99
100
  // scoped
101
102
  function getObsValue (valueOrObs) {
103
    if (fixedIndexing && !isObservable(valueOrObs)) {
104
      valueOrObs = Value(valueOrObs)
105
    }
106
    return valueOrObs
107
  }
108
109
  function put (key, valueOrObs) {
110
    tryInvoke(objectReleases[key])
111
    sources[key] = valueOrObs
112
    if (binder.live) {
113
      objectReleases[key] = bind(key, valueOrObs)
114
    }
115
    object[key] = resolve(valueOrObs)
116
  }
117
118
  function bind (key, valueOrObs) {
119
    return typeof valueOrObs === 'function' ? valueOrObs(updateKey.bind(this, key)) : null
120
  }
121
122
  function updateKey (key, value) {
123
    object[key] = value
124
    binder.broadcast()
125
  }
126
127
  function listen () {
128
    Object.keys(sources).forEach(function (key) {
129
      objectReleases[key] = bind(key, sources[key])
130
    })
131
132
    if (opts && opts.onListen) {
133
      var release = opts.onListen()
134
      if (typeof release === 'function') {
135
        releases.push(release)
136
      }
137
    }
138
  }
139
140
  function unlisten () {
141
    Object.keys(sources).forEach(function (key) {
142
      tryInvoke(objectReleases[key])
143
      delete objectReleases[key]
144
    })
145
146
    while (releases.length) {
147
      tryInvoke(releases.pop())
148
    }
149
150
    if (opts && opts.onUnlisten) {
151
      opts.onUnlisten()
152
    }
153
  }
154
155
  function update () {
156
    var changed = false
157
    Object.keys(sources).forEach(function (key) {
158
      var newValue = resolve(sources[key])
159
      if (!isSame(newValue, object[key], comparer)) {
160
        object[key] = newValue
161
        changed = true
162
      }
163
    })
164
    return changed
165
  }
166
}
167
168
function tryInvoke (func) {
169
  if (typeof func === 'function') {
170
    func()
171
  }
172
}
173