Contents

# This GraphQL Schema performs operations on numbers.
# It can perform operations on values you give it and return values
# It also maintains some state which can be updated or read

# You can reduce a list of values to a single value
REDUCERS = {
  "SUM" => -> (values) { [values.inject(&:+)] },
  "MAX" => :max.to_proc,
  "MIN" => :min.to_proc,
}

ReducerEnum = GraphQL::EnumType.define do
  REDUCERS.map do |op_name, op_proc|
    value(op_name)
  end
end

# You can make a new list by transforming each member
MAPPERS = {
  "ADD" => -> (val, arg) { val + arg },
  "SUB" => -> (val, arg) { val - arg },
  "EQ" => -> (val, arg) { val == arg ? 1 : 0},
}

MapperEnum = GraphQL::EnumType.define do
  MAPPERS.map do |op_name, op_proc|
    value(op_name)
  end
end

# Input a list of integers
ListOfInts = GraphQL::INT_TYPE.to_list_type

# Expose a list of values and perform operations
ValuesType = GraphQL::ObjectType.define do
  field :values, ListOfInts do
    resolve -> (obj, _args, _ctx) { obj }
  end

  # Get a single value based on the values in this list
  field :reduce, types.Int do
    argument :operation, !ReducerEnum
    resolve -> (obj, args, ctx)  {
      reduce_name = args[:operation]
      reduce_fn = REDUCERS[reduce_name]
      reduce_fn.call(obj)
    }
  end

  # Handle self-referential fields by wrapping the type in a proc.
  # It will be lazy-eval'ed
  field :map, -> { ValuesType } do
    argument :operation, !MapperEnum
    argument :argument, !types.Int
    resolve -> (obj, args, ctx) {
      op_arg = args[:argument]
      op_name = args[:operation]
      op_func = MAPPERS[op_name]
      obj.map { |item| op_func.call(item, op_arg) }
    }
  end
end

QueryType = GraphQL::ObjectType.define do
  name("Query")

  field :perform, ValuesType do
    argument :initial, !ListOfInts
    resolve -> (obj, args, ctx) { args[:initial] }
  end
end

CalculatorSchema = GraphQL::Schema.new(query: QueryType)

Version data entries

1 entries across 1 versions & 1 rubygems

Version	Path
graphql-0.10.2	spec/support/calculator_schema.rb