Class: Volt::AttributeBinding

Inherits:
BaseBinding show all
Defined in:
lib/volt/page/bindings/attribute_binding.rb

Instance Attribute Summary

Attributes inherited from BaseBinding

#binding_name, #context, #target, #volt_app

Instance Method Summary collapse

Methods inherited from BaseBinding

#browser, #dom_section, #getter_fail

Constructor Details

#initialize(volt_app, target, context, binding_name, attribute_name, getter, setter) ⇒ AttributeBinding

Returns a new instance of AttributeBinding.



6
7
8
9
10
11
12
13
14
 
# File 'lib/volt/page/bindings/attribute_binding.rb', line 6

def initialize(volt_app, target, context, binding_name, attribute_name, getter, setter)
  super(volt_app, target, context, binding_name)

  @attribute_name = attribute_name
  @getter         = getter
  @setter         = setter

  setup
end

Instance Method Details

#changed(event = nil) ⇒ Object 



65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
 
# File 'lib/volt/page/bindings/attribute_binding.rb', line 65

def changed(event = nil)
  case @attribute_name
    when 'value'
      current_value = `#{element}.val() || ''`
    else
      current_value = `#{element}.is(':checked')`
  end

  if @is_radio
    if current_value
      # if it is a radio button and its checked
      @context.instance_exec(@selected_value, &@setter)
    end
  else
    @context.instance_exec(current_value, &@setter)
  end
end

#element ⇒ Object 



83
84
85
 
# File 'lib/volt/page/bindings/attribute_binding.rb', line 83

def element
  @element ||= `$('#' + #{binding_name})`
end

#invalidate ⇒ Object

On select boxes, when an option is added/changed, we want to run update again. By calling invalidate, it will run at most once on the next tick.



140
141
142
 
# File 'lib/volt/page/bindings/attribute_binding.rb', line 140

def invalidate
  @computation.invalidate!
end

#remove ⇒ Object 



152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
 
# File 'lib/volt/page/bindings/attribute_binding.rb', line 152

def remove
  # Unbind events, leave the element there since attribute bindings
  # aren't responsible for it being there.
  case @attribute_name
    when 'value'
      if @is_select
        `#{element}.off('change.attrbind')`
        `#{element}.off('invalidate')`
      elsif @is_hidden
        `#{element}.unwatch('value')`
      else
        `#{element}.off('input.attrbind', #{nil})`
      end
    when 'checked'
      `#{element}.off('change.attrbind', #{nil})`
  end

  if @computation
    @computation.stop
    @computation = nil
  end

  @string_template_renderer.remove if @string_template_renderer
  @string_template_renderer_computation.stop if @string_template_renderer_computation

  # Clear any references
  @target  = nil
  @context = nil
  @getter  = nil
end

#remove_anchors ⇒ Object 



183
184
185
 
# File 'lib/volt/page/bindings/attribute_binding.rb', line 183

def remove_anchors
  fail 'attribute bindings do not have anchors, can not remove them'
end

#setup ⇒ Object 



16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
 
# File 'lib/volt/page/bindings/attribute_binding.rb', line 16

def setup
  if `#{element}.is('select')`
    @is_select = true
  elsif `#{element}.is('[type=hidden]')`
    @is_hidden = true
  elsif `#{element}.is('[type=radio]')`
    @is_radio = true
    @selected_value = `#{element}.attr('value') || ''`
  elsif `#{element}.is('option')`
    @is_option = true
  end

  if @is_option
  else
    # Bind so when this value updates, we update
    case @attribute_name
      when 'value'
        changed_event = Proc.new { changed }
        if @is_select
          `#{element}.on('change.attrbind', #{changed_event})`

          invalidate_proc = Proc.new { invalidate }
          `#{element}.on('invalidate', #{invalidate_proc})`
        elsif @is_hidden
          `#{element}.watch('value', #{changed_event})`
        else
          `#{element}.on('input.attrbind', #{changed_event})`
        end
      when 'checked'
        changed_event = proc { |event| changed(event) }
        `#{element}.on('change.attrbind', #{changed_event})`
    end
  end

  # Listen for changes
  @computation = lambda do
    begin
      @context.instance_eval(&@getter)
    rescue => e
      getter_fail(e)
      ''
    end
  end.watch_and_resolve!(
    method(:update),
    method(:getter_fail)
  )

end

#update(new_value) ⇒ Object 



87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
 
# File 'lib/volt/page/bindings/attribute_binding.rb', line 87

def update(new_value)
  if @attribute_name == 'checked'
    update_checked(new_value)
    return
  end

  # Stop any previous reactive template computations
  @string_template_renderer_computation.stop if @string_template_renderer_computation
  @string_template_renderer.remove if @string_template_renderer

  if new_value.is_a?(StringTemplateRenderer)
    # We don't need to refetch the whole reactive template to
    # update, we can just depend on it and update directly.
    @string_template_renderer = new_value

    @string_template_renderer_computation = lambda do
      self.value = @string_template_renderer.html
    end.watch!
  else
    new_value = '' if new_value.is_a?(NilMethodCall) || new_value.nil?

    self.value = new_value
  end
end

#update_checked(value) ⇒ Object 



144
145
146
147
148
149
150
 
# File 'lib/volt/page/bindings/attribute_binding.rb', line 144

def update_checked(value)
  value = false if value.is_a?(NilMethodCall) || value.nil?

  value = (@selected_value == value) if @is_radio

  `#{element}.prop('checked', #{value})`
end

#value=(val) ⇒ Object 



112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
 
# File 'lib/volt/page/bindings/attribute_binding.rb', line 112

def value=(val)
  case @attribute_name
    when 'value'
      if @is_option
        # When a new option is added, we trigger the invalidate event on the
        # parent select so it will re-run update on the next tick and set
        # the correct option.
        `#{element}.parent('select').trigger('invalidate');`
      end
      # TODO: only update if its not the same, this keeps it from moving the
      # cursor in text fields.
      `#{element}.val(#{val})` if val != `(#{element}.val() || '')`
    when 'disabled'
      # Disabled is handled specially, you can either return a boolean:
      # (true being disabled, false not disabled), or you can optionally
      # include the "disabled" string. (or any string)
      if val != false && val.present?
        `#{element}.attr('disabled', 'disabled')`
      else
        `#{element}.removeAttr('disabled')`
      end
    else
      `#{element}.attr(#{@attribute_name}, #{val})`
  end
end