git ssb

1
var applyProperties = require('./lib/apply-properties')
2
var isObservable = require('./is-observable')
3
var parseTag = require('./lib/parse-tag')
4
var caches = new global.WeakMap()
5
6
module.exports = function (tag, attributes, children) {
7
  return Element(global.document, null, tag, attributes, children)
8
}
9
10
module.exports.forDocument = function (document, namespace) {
11
  return Element.bind(this, document, namespace)
12
}
13
14
module.exports.destroy = function (node) {
15
  unbind(node)
16
  caches.delete(node)
17
}
18
19
function Element (document, namespace, tagName, properties, children) {
20
  if (!children && (Array.isArray(properties) || isText(properties))) {
21
    children = properties
22
    properties = null
23
  }
24
25
  properties = properties || {}
26
27
  var tag = parseTag(tagName, properties, namespace)
28
  var node = namespace
29
    ? document.createElementNS(namespace, tag.tagName)
30
    : document.createElement(tag.tagName)
31
32
  if (tag.id) {
33
    node.id = tag.id
34
  }
35
36
  if (tag.classes && tag.classes.length) {
37
    node.className = tag.classes.join(' ')
38
  }
39
40
  var data = {
41
    targets: new Map(),
42
    bindings: []
43
  }
44
45
  caches.set(node, data)
46
  var hooks = applyProperties(node, properties, data)
47
  if (children != null) {
48
    appendChild(document, node, data, children)
49
  }
50
51
  if (Array.isArray(hooks)) {
52
    hooks.forEach(function (v) {
53
      data.bindings.push(new HookBinding(v, node))
54
    })
55
  }
56
57
  return node
58
}
59
60
function appendChild (document, target, data, node) {
61
  if (Array.isArray(node)) {
62
    node.forEach(function (child) {
63
      appendChild(document, target, data, child)
64
    })
65
  } else if (isObservable(node)) {
66
    var nodes = getNodes(document, resolve(node))
67
    nodes.forEach(append, target)
68
    data.targets.set(node, nodes)
69
    data.bindings.push(new Binding(bind, document, node, data))
70
  } else {
71
    target.appendChild(getNode(document, node))
72
  }
73
}
74
75
function append (child) {
76
  this.appendChild(child)
77
}
78
79
function bind (document, obs, data) {
80
  return obs(function (value) {
81
    var oldNodes = data.targets.get(obs)
82
    var newNodes = getNodes(document, value)
83
    if (oldNodes) {
84
      replace(oldNodes, newNodes)
85
      data.targets.set(obs, newNodes)
86
    }
87
  })
88
}
89
90
function replace (oldNodes, newNodes) {
91
  // TODO: optmize to not reinsert nodes that are already in correct position!
92
  var parent = oldNodes[oldNodes.length - 1].parentNode
93
  var marker = oldNodes[oldNodes.length - 1].nextSibling
94
  oldNodes.filter(function (node) {
95
    return !~newNodes.indexOf(node)
96
  }).forEach(function (node) {
97
    parent.removeChild(node)
98
    unbind(node)
99
  })
100
  if (marker) {
101
    newNodes.forEach(function (node) {
102
      parent.insertBefore(node, marker)
103
    })
104
  } else {
105
    newNodes.forEach(function (node) {
106
      parent.appendChild(node)
107
      rebind(node)
108
    })
109
  }
110
}
111
112
function isText (value) {
113
  return typeof value === 'string' || typeof value === 'number' || typeof value === 'boolean'
114
}
115
116
function getNode (document, nodeOrText) {
117
  if (nodeOrText == null) {
118
    return document.createTextNode('')
119
  } else if (isText(nodeOrText)) {
120
    return document.createTextNode(nodeOrText.toString())
121
  } else {
122
    return nodeOrText
123
  }
124
}
125
126
function getNodes (document, nodeOrNodes) {
127
  if (Array.isArray(nodeOrNodes)) {
128
    if (nodeOrNodes.length) {
129
      var result = []
130
      nodeOrNodes.forEach(function (item) {
131
        if (Array.isArray(item)) {
132
          getNodes(document, item).forEach(push, result)
133
        } else {
134
          result.push(getNode(document, item))
135
        }
136
      })
137
      return result.map(getNode.bind(this, document))
138
    } else {
139
      return [getNode(document, null)]
140
    }
141
  } else {
142
    return [getNode(document, nodeOrNodes)]
143
  }
144
}
145
146
function rebind (node) {
147
  if (node.nodeType === 1) {
148
    var data = caches.get(node)
149
    if (data) {
150
      data.bindings.forEach(invokeBind)
151
    }
152
    for (var i = 0; i < node.childNodes.length; i++) {
153
      rebind(node.childNodes[i])
154
    }
155
  }
156
}
157
158
function unbind (node) {
159
  if (node.nodeType === 1) {
160
    var data = caches.get(node)
161
    if (data) {
162
      data.bindings.forEach(invokeUnbind)
163
    }
164
    for (var i = 0; i < node.childNodes.length; i++) {
165
      unbind(node.childNodes[i])
166
    }
167
  }
168
}
169
170
function invokeBind (binding) {
171
  binding.bind()
172
}
173
174
function invokeUnbind (binding) {
175
  binding.unbind()
176
}
177
178
function push (item) {
179
  this.push(item)
180
}
181
182
function resolve (source) {
183
  return typeof source === 'function' ? source() : source
184
}
185
186
function tryInvoke (func) {
187
  if (typeof func === 'function') {
188
    func()
189
  }
190
}
191
192
function HookBinding (fn, element) {
193
  this.element = element
194
  this.fn = fn
195
  this.bind()
196
}
197
198
HookBinding.prototype = {
199
  bind: function () {
200
    if (!this.bound) {
201
      this._release = this.fn(this.element)
202
      this.bound = true
203
    }
204
  },
205
  unbind: function () {
206
    if (this.bound && typeof this._release === 'function') {
207
      this._release()
208
      this._release = null
209
      this.bound = false
210
    }
211
  }
212
}
213
214
function Binding (fn, document, obs, data) {
215
  this.document = document
216
  this.obs = obs
217
  this.data = data
218
  this.fn = fn
219
  this.bind()
220
}
221
222
Binding.prototype = {
223
  bind: function () {
224
    if (!this.bound) {
225
      this._release = this.fn(this.document, this.obs, this.data)
226
      this.bound = true
227
    }
228
  },
229
  unbind: function () {
230
    if (this.bound && typeof this._release === 'function') {
231
      this._release()
232
      this._release = null
233
      this.bound = false
234
    }
235
  }
236
}
237