Extra.hs

-- Copyright 2022 United States Government as represented by the Administrator
-- of the National Aeronautics and Space Administration. All Rights Reserved.
--
-- Disclaimers
--
-- Licensed under the Apache License, Version 2.0 (the "License"); you may
-- not use this file except in compliance with the License. You may obtain a
-- copy of the License at
--
--      https://www.apache.org/licenses/LICENSE-2.0
--
-- Unless required by applicable law or agreed to in writing, software
-- distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
-- WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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--
-- | Auxiliary functions for working with JSON values.
module Data.Aeson.Extra
    ( mergeObjects )
  where

-- External imports
import Data.Aeson        (Value (Null, Object))
import Data.Aeson.KeyMap (union)

-- | Merge two JSON values.
--
-- Fails if the values are not objects or null.
mergeObjects :: Value -> Value -> Value
mergeObjects (Object m1) (Object m2) = Object (union m1 m2)
mergeObjects obj         Null        = obj
mergeObjects Null        obj         = obj
mergeObjects _           _           = error "The values passed are not objects"