git ssb

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