Class: Parse::Constraint::EmptyConstraint

Inherits:

Parse::Constraint

• Object
• Parse::Constraint
• Parse::Constraint::EmptyConstraint

Defined in:

lib/parse/query/constraints.rb

Overview

Checks whether an array field contains any elements

q.where :field.empty => true

See Also:

• NullabilityConstraint

Instance Attribute Summary

Attributes inherited from Parse::Constraint

#operand, #operation, #operator, #value

Instance Method Summary

• #build ⇒ Hash

  The compiled constraint.

• #empty ⇒ ExistsConstraint

  A registered method on a symbol to create the constraint.

Methods inherited from Parse::Constraint

#as_json, constraint_keyword, create, formatted_value, #formatted_value, #initialize, #key, #precedence, register, #to_s

Constructor Details

This class inherits a constructor from Parse::Constraint

Instance Method Details

#build ⇒ Hash

Returns the compiled constraint.

Returns:

• (Hash) —

  the compiled constraint.

# File 'lib/parse/query/constraints.rb', line 356

def build
  # if nullability is equal true, then $empty should be set to false
  value = formatted_value

  unless value == true || value == false
    raise ArgumentError, "#{self.class}: Non-Boolean value passed, it must be either `true` or `false`"
  end

  return { "#{@operation.operand}.0" => { key => !value } }
end

#empty ⇒ ExistsConstraint

A registered method on a symbol to create the constraint.

Examples:

q.where :field.empty => true

Returns:

• (ExistsConstraint)

# File 'lib/parse/query/constraints.rb', line 352

constraint_keyword :$exists