Class: Parse::Constraint::ArrayEmptyOrNilConstraint

Inherits:

Parse::Constraint

Object
Parse::Constraint
Parse::Constraint::ArrayEmptyOrNilConstraint

show all

Defined in:: lib/parse/query/constraints.rb

Overview

Note:

Uses index-friendly operations where possible.

Array empty or nil constraint - matches arrays that are empty OR nil/missing. This is useful for finding records where an array field has no values, whether it’s explicitly empty or was never set.

q.where :tags.empty_or_nil => true   # matches [] or nil/missing
q.where :tags.empty_or_nil => false  # matches non-empty arrays only

Instance Attribute Summary

Attributes inherited from Parse::Constraint

#operand, #operation, #operator, #value

Instance Method Summary collapse

#build ⇒ Hash

The compiled constraint using aggregation pipeline.
#empty_or_nil ⇒ ArrayEmptyOrNilConstraint

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 using aggregation pipeline.

Returns:

(Hash) —

the compiled constraint using aggregation pipeline.

# File 'lib/parse/query/constraints.rb', line 708

def build
  value = formatted_value
  unless value == true || value == false
    raise ArgumentError, "#{self.class}: Value must be true or false"
  end

  # Use formatted field name for proper Parse field mapping
  field_name = Parse::Query.format_field(@operation.operand)

  if value
    # Match empty array OR nil/missing field
    # Use explicit $eq for empty array check (more reliable through Parse Server)
    pipeline = [
      {
        "$match" => {
          "$or" => [
            { field_name => { "$exists" => true, "$eq" => [] } },
            { field_name => { "$exists" => false } },
            { field_name => { "$eq" => nil } },
          ],
        },
      },
    ]
  else
    # Match non-empty arrays (must exist, not nil, and not empty)
    # Use $and to combine multiple conditions without duplicate keys
    pipeline = [
      {
        "$match" => {
          "$and" => [
            { field_name => { "$exists" => true } },
            { field_name => { "$ne" => nil } },
            { field_name => { "$ne" => [] } },
          ],
        },
      },
    ]
  end

  { "__aggregation_pipeline" => pipeline }
end

#empty_or_nil ⇒ `ArrayEmptyOrNilConstraint`

A registered method on a symbol to create the constraint.

Examples:

q.where :field.empty_or_nil => true