Module: Volt::Models::Helpers::Dirty

Included in:
Volt::Model
Defined in:
lib/volt/models/helpers/dirty.rb

Overview

The dirty module provides helper methods for working with and tracking previous values on model attributes.

Instance Method Summary collapse

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(method_name, *args, &block) ⇒ Object

Handle change and was method calls Example: name_was or name_changes



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# File 'lib/volt/models/helpers/dirty.rb', line 66

def method_missing(method_name, *args, &block)
  # Quick check to see if changes or was are being called, this check
  # keeps us from needing to parse out the parts if we're not going
  # to use them.
  if method_name =~ /[_](changes|was)$/
    # Break apart the method call
    # TODO: no destructuring because of https://github.com/opal/opal/issues/663
    *parts = method_name.to_s.split('_')
    action = parts.pop
    key = parts.join('_').to_sym

    # Handle changes or was calls.
    case action
    when 'changes'
      return changes(key)
    when 'was'
      return was(key)
    end
  end

  # Otherwise, run super
  super
end

Instance Method Details

#attribute_will_change!(attribute_name, old_value) ⇒ Object 



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# File 'lib/volt/models/helpers/dirty.rb', line 57

def attribute_will_change!(attribute_name, old_value)
  # Don't track nil models
  old_value = nil if old_value.nil?

  (changed_attributes[attribute_name] ||= []) << old_value
end

#changed?(key = nil) ⇒ Boolean

Return true if key has changed

Returns:



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# File 'lib/volt/models/helpers/dirty.rb', line 13

def changed?(key = nil)
  if key
    # return the changed values for the keys
    changed_attributes.key?(key)
  else
    changed_attributes.present?
  end
end

#changed_attributes ⇒ Object

Return the list of attributes that have changed since the last ‘save’ event.



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# File 'lib/volt/models/helpers/dirty.rb', line 8

def changed_attributes
  @changed_attributes ||= {}
end

#changes(key) ⇒ Object

Grab all previous versions of for key



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# File 'lib/volt/models/helpers/dirty.rb', line 23

def changes(key)
  changed_attributes[key]
end

#clear_tracked_changes! ⇒ Object

Clear changed attributes



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# File 'lib/volt/models/helpers/dirty.rb', line 41

def clear_tracked_changes!
  @changed_attributes = {}
end

#revert_changes! ⇒ Object

Reverts the model attributes back to the pre-change values.



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# File 'lib/volt/models/helpers/dirty.rb', line 46

def revert_changes!
  # Reassign the first value since we started tracking
  if @changed_attributes
    @changed_attributes.each_pair do |key, value|
      @attributes[key] = value.first
    end
  end

  clear_tracked_changes!
end

#was(key) ⇒ Object

Grab the previous value for the key



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# File 'lib/volt/models/helpers/dirty.rb', line 28

def was(key)
  val = changed_attributes[key]

  # Doing val && val[0] doesn't work in opal
  # https://github.com/opal/opal/issues/664
  if val
    val[0]
  else
    nil
  end
end