Class: Datacaster::HashMapper

Inherits:
Base
  • Object
show all
Defined in:
lib/datacaster/hash_mapper.rb

Instance Method Summary collapse

Methods included from Mixin

#&, #*, #call, #call_with_runtime, #cast_errors, #i18n_key, #i18n_map_keys, #i18n_scope, #i18n_vars, #then, #with_context, #with_object_context, #with_runtime, #|

Constructor Details

#initialize(fields) ⇒ HashMapper

Returns a new instance of HashMapper.



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# File 'lib/datacaster/hash_mapper.rb', line 3

def initialize(fields)
  keys = fields.keys.flatten
  if keys.length != keys.uniq.length
    intersection = keys.select { |k| keys.count(k) > 1 }.uniq.sort
    raise ArgumentError.new("When using transform_to_hash([:a, :b, :c] => validator), " \
      "each key should not be mentioned more than once on the left-hand-side. Instead, got these " \
      "keys mentioned twice or more: #{intersection.inspect}."
    )
  end

  @fields = fields
end

Instance Method Details

#cast(object, runtime:) ⇒ Object 



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# File 'lib/datacaster/hash_mapper.rb', line 16

def cast(object, runtime:)
  errors = {}
  result = {}

  @fields.each do |key, validator|
    new_value = runtime.ignore_checks! { validator.with_runtime(runtime).(object) }

    # transform_to_hash([:a, :b, :c] => pick(:a, :b, :c) & ...)
    if key.is_a?(Array)
      unwrapped = new_value.valid? ? new_value.value : new_value.raw_errors

      if key.length != unwrapped.length
        raise TypeError, "When using transform_to_hash([:a, :b, :c] => validator), validator should return Array "\
          "with number of elements equal to the number of elements in left-hand-side array.\n" \
          "Got the following (values or errors) instead: #{key.inspect} => #{unwrapped.inspect}."
      end
    end

    if new_value.valid?
      if key.is_a?(Array)
        key.zip(new_value.value) do |new_key, new_key_value|
          result[new_key] = new_key_value
          runtime.checked_key!(new_key)
        end
      else
        result[key] = new_value.value
        runtime.checked_key!(key)
      end
    else
      if key.is_a?(Array)
        errors = Utils.merge_errors(errors, key.zip(new_value.raw_errors).to_h)
      else
        errors = Utils.merge_errors(errors, {key => new_value.raw_errors})
      end
    end
  end

  runtime.will_check!
  result.keys.each { |key| runtime.checked_key!(key) }

  errors.delete_if { |_, v| v.empty? }

  if errors.empty?
    # All unchecked key-value pairs of initial hash are passed through, and eliminated by ContextNode
    # at the end of the chain. If we weren't dealing with the hash, then ignore that.
    result_hash =
      if object.is_a?(Hash)
        object.merge(result)
      else
        result
      end

    result_hash.keys.each { |k| result_hash.delete(k) if result_hash[k] == Datacaster.absent }
    Datacaster.ValidResult(result_hash)
  else
    Datacaster.ErrorResult(errors)
  end
end

#inspect ⇒ Object 



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# File 'lib/datacaster/hash_mapper.rb', line 75

def inspect
  field_descriptions =
    @fields.map do |k, v|
      "#{k.inspect} => #{v.inspect}"
    end

  "#<Datacaster::HashMapper {#{field_descriptions.join(', ')}}>"
end