git ssb

1
var isObservable = require('../is-observable')
2
var Set = require('../set')
3
var watch = require('../watch')
4
5
module.exports = applyProperties
6
7
function applyProperties (target, properties, data) {
8
  var classList = Set()
9
  if (target.className) {
10
    classList.add(target.className)
11
  }
12
13
  for (var key in properties) {
14
    var valueOrObs = properties[key]
15
    var value = resolve(valueOrObs)
16
17
    if (key === 'style') {
18
      // TODO: handle observable at root for style objects
19
      for (var k in value) {
20
        var styleObs = isObservable(value[k]) ? value[k] : null
21
        if (styleObs) {
22
          data.bindings.push(new Binding(bindStyle, target, styleObs, k))
23
        } else {
24
          target.style.setProperty(k, value[k])
25
        }
26
      }
27
    } else if (key === 'hooks') {
28
      if (Array.isArray(value)) {
29
        value.forEach(function (v) {
30
          data.bindings.push(new HookBinding(v, target))
31
        })
32
      }
33
    } else if (key === 'attributes') {
34
      for (var k in value) {
35
        var attrObs = isObservable(value[k]) ? value[k] : null
36
        if (attrObs) {
37
          data.bindings.push(new Binding(bindAttr, target, attrObs, k))
38
        } else {
39
          target.setAttribute(k, value[k])
40
        }
41
      }
42
    } else if (key === 'events') {
43
      for (var name in value) {
44
        target.addEventListener(name, value[name], false)
45
      }
46
    } else if (key.slice(0, 3) === 'ev-') {
47
      target.addEventListener(key.slice(3), value, false)
48
    } else if (key === 'className' || key === 'classList') {
49
      if (Array.isArray(valueOrObs)) {
50
        valueOrObs.forEach(function (v) {
51
          classList.add(v)
52
        })
53
      } else {
54
        classList.add(valueOrObs)
55
      }
56
    } else {
57
      target[key] = value
58
      var obs = isObservable(valueOrObs) ? valueOrObs : null
59
      if (obs) {
60
        data.bindings.push(new Binding(bind, target, obs, key))
61
      }
62
    }
63
  }
64
65
  if (classList.getLength()) {
66
    data.bindings.push(new Binding(bindClassList, target, classList, 'className'))
67
  }
68
}
69
70
function bindClassList (target, obs, key) {
71
  return watch(obs, function (value) {
72
    value = [].concat.apply([], value).filter(present).join(' ')
73
    if (value || target[key]) {
74
      target[key] = value
75
    }
76
  })
77
}
78
79
function bindStyle (target, styleObs, key) {
80
  return watch(styleObs, function (value) {
81
    target.style.setProperty(key, value)
82
  })
83
}
84
85
function bindAttr (target, attrObs, key) {
86
  return watch(attrObs, function (value) {
87
    if (value == null) {
88
      target.removeAttribute(key)
89
    } else {
90
      target.setAttribute(key, value)
91
    }
92
  })
93
}
94
95
function bind (target, obs, key) {
96
  return watch(obs, function (toValue) {
97
    var fromValue = target.getAttribute(key)
98
    if (fromValue !== toValue) {
99
      target.setAttribute(key, toValue)
100
    }
101
  })
102
}
103
104
function present (val) {
105
  return val != null
106
}
107
108
function resolve (source) {
109
  return typeof source === 'function' ? source() : source
110
}
111
112
function Binding (fn, element, source, key) {
113
  this.element = element
114
  this.source = source
115
  this.key = key
116
  this.fn = fn
117
  this.bound = false
118
}
119
120
Binding.prototype = {
121
  bind: function () {
122
    if (!this.bound) {
123
      this._release = this.fn(this.element, this.source, this.key)
124
      this.bound = true
125
    }
126
  },
127
  unbind: function () {
128
    if (this.bound) {
129
      this._release()
130
      this._release = null
131
      this.bound = false
132
    }
133
  }
134
}
135
136
function HookBinding (fn, element) {
137
  this.element = element
138
  this.fn = fn
139
  this.bound = false
140
}
141
142
HookBinding.prototype = {
143
  bind: function () {
144
    if (!this.bound) {
145
      this._release = this.fn(this.element)
146
      this.bound = true
147
    }
148
  },
149
  unbind: function () {
150
    if (this.bound && typeof this._release === 'function') {
151
      this._release()
152
      this._release = null
153
      this.bound = false
154
    }
155
  }
156
}
157