DataWeave输出异常：apple数组元素id出现banana前缀问题排查

执行DataWeave脚本后，Apple数组的元素ID被错误添加Banana前缀（如banana-apple-1），但预期结果应为apple-1。以下是相关输入、脚本及异常输出：

输入JSON #

{
    "apple":{
        "options":[
            {
                "id": "1",
                "name": "apple-one"
            },
            {
                "id": "2",
                "name": "apple-two"
            },
            {
                "id": "3",
                "name": "apple-three"
            }
        ]
    },
    "banana":{
        "options":[
            {
                "id": "4",
                "name": "banana-four"
            },
            {
                "id": "5",
                "name": "banana-five"
            },
            {
                "id": "6",
                "name": "banana-six"
            }
        ]
    },
    "orange":{
        "options":[
            {
                "id": "7",
                "name": "orange-seven"
            },
            {
                "id": "8",
                "name": "orange-eight"
            },
            {
                "id": "9",
                "name": "orange-nine"
            }
        ]
    }
}

原始DataWeave脚本 #

%dw 2.0
output application/json
---
payload.apple.options map ($ mapObject ((value, key, index) -> {
    ((key) : "apple-" ++ value) if ((key) as String == "id"),
    ((key) : value ) if ((key) as String != "id")
        }
    )
)

++


payload.banana.options map ($ mapObject ((value, key, index) -> {
    ((key) : "banana-" ++ value) if ((key) as String == "id"),
    ((key) : value ) if ((key) as String != "id")
        }
    )
)

异常输出 #

[
  {
    "id": "banana-apple-1",
    "name": "apple-one"
  },
  {
    "id": "banana-apple-2",
    "name": "apple-two"
  },
  {
    "id": "banana-apple-3",
    "name": "apple-three"
  },
  {
    "id": "banana-4",
    "name": "banana-four"
  },
  {
    "id": "banana-5",
    "name": "banana-five"
  },
  {
    "id": "banana-6",
    "name": "banana-six"
  }
]

问题原因分析 #

按照提供的脚本逻辑，两个数组是独立处理后再拼接，理论上Apple的ID不会被添加Banana前缀。出现异常的可能原因包括：

• 脚本解析错误：括号、换行等格式问题导致DataWeave错误地将两个map操作解析为嵌套关系，使得Apple数组的处理结果被Banana的逻辑二次加工。
• Playground环境问题：DataWeave Playground的缓存或临时bug，导致运行的脚本与编辑的版本不一致。

修正后的脚本 #

通过简化逻辑、提取公共函数的方式，避免格式错误和重复代码，确保逻辑正确：

%dw 2.0
output application/json
// 提取公共函数，统一处理ID前缀
fun addIdPrefix(items, prefix) = 
    items map ($ mapObject (value, key) -> 
        (key): if(key == "id") prefix ++ value else value
    )
---
// 分别处理两个数组后拼接
addIdPrefix(payload.apple.options, "apple-") ++ addIdPrefix(payload.banana.options, "banana-")

预期输出 #

[
  {
    "id": "apple-1",
    "name": "apple-one"
  },
  {
    "id": "apple-2",
    "name": "apple-two"
  },
  {
    "id": "apple-3",
    "name": "apple-three"
  },
  {
    "id": "banana-4",
    "name": "banana-four"
  },
  {
    "id": "banana-5",
    "name": "banana-five"
  },
  {
    "id": "banana-6",
    "name": "banana-six"
  }
]

内容的提问来源于stack exchange，提问作者Kalyan Mudi