Javascript 合并两个JSONata表达式

我使用JSONata执行JSON到JSON的转换

出于一些独特的原因，我想合并两个JSONata表达式：

例如：

父表达式：

var script = `
{
      "data":
      {
          "name" : data.payload.Name.(FirstName & ' ' & LastName),    
          "alias": data.payload.Name.(Salutation & ' ' & FirstName),
          "active": data.payload.Status = 'New' ? true : false,
          "signature": "Have good day ," & data.payload.Name.FirstName & "!"
       }       
  }
`;

{
   "source" : source
}

{
  "data": {
     "email" : data.payload.Email
   }
}

我还有一些简单的赋值类型的JSONata表达式，如：

表达式1:

var script = `
{
      "data":
      {
          "name" : data.payload.Name.(FirstName & ' ' & LastName),    
          "alias": data.payload.Name.(Salutation & ' ' & FirstName),
          "active": data.payload.Status = 'New' ? true : false,
          "signature": "Have good day ," & data.payload.Name.FirstName & "!"
       }       
  }
`;

{
   "source" : source
}

{
  "data": {
     "email" : data.payload.Email
   }
}

表达式2:

var script = `
{
      "data":
      {
          "name" : data.payload.Name.(FirstName & ' ' & LastName),    
          "alias": data.payload.Name.(Salutation & ' ' & FirstName),
          "active": data.payload.Status = 'New' ? true : false,
          "signature": "Have good day ," & data.payload.Name.FirstName & "!"
       }       
  }
`;

{
   "source" : source
}

{
  "data": {
     "email" : data.payload.Email
   }
}

我想将以上两个表达式添加到使用

script

定义的表达式中

因此，在添加这两个表达式之后，我应该能够得到：

var script = `
{
      "source": source,
      "data":
      {
          "name" : data.payload.Name.(FirstName & ' ' & LastName),    
          "alias": data.payload.Name.(Salutation & ' ' & FirstName),
          "active": data.payload.Status = 'New' ? true : false,
          "signature": "Have good day ," & data.payload.Name.FirstName & "!",
          "email": data.payload.Email
       }       
  }
`;

如何使用javascript/JSONata

背景和约束条件：

子表达式（示例中的表达式1和2）（应该添加到父表达式中）将始终是简单的赋值，如

“a”：x.y.z或“b”：x

子表达式可能已存在于父表达式中。在这种情况下，它将取代赋值

我还想从父表达式中删除一些json路径（当然，如果存在的话），比如删除路径

data.Email

我做了什么？：

var script = `
{
      "data":
      {
          "name" : data.payload.Name.(FirstName & ' ' & LastName),    
          "alias": data.payload.Name.(Salutation & ' ' & FirstName),
          "active": data.payload.Status = 'New' ? true : false,
          "signature": "Have good day ," & data.payload.Name.FirstName & "!"
       }       
  }
`;

{
   "source" : source
}

{
  "data": {
     "email" : data.payload.Email
   }
}

• 我尝试将JSONata脚本转换为JSON，方法是将值放在双引号下，并使用escape（）函数对值进行编码
• 一旦我有了JSON，我就会寻找子表达式中提到的路径（比如data.Email）
  • 如果路径存在：替换其值
  • 如果路径不存在：创建路径并赋值
  • 如果路径应该被删除：只需删除它
• 一旦我处理完上面的JSON， 通过使用一堆正则表达式删除引号，然后应用unescape（）方法进行解码，我将其转换为JSONata脚本

• 这种方法的问题是：
  • 不可靠（正则表达式匹配和替换不是完全可靠的）
  • 我不确定是否每个JSONata（不声明任何函数）都可以始终转换为有效的JSON

---

我认为最好的办法是将表达式翻译成JSONata，然后将它们合并成新的AST

下面是一个超级简单的示例：

const ast1 = jsonata(expr1).ast();
const ast2 = jsonata(expr1).ast();

if (ast1.type !== "unary" || ast2.type!== "unary") throw Error("Only support unary expressions")

const combinedAst = {
  "type": "unary",
  "value": "{",
  "lhs": [...ast1.lhs, ast2.lhs]   
 }

 // TODO: Serialize the AST or inject it into jsonata() 

问题是如何处理你的新AST。在我的例子中，我还编写了一个自定义序列化程序，将AST转换回JSONata字符串，并对其进行计算

---

使用中的AST 表达式1的AST

{
  "type": "unary",
  "value": "{",
  "position": 1,
  "lhs": [
    [
      {
        "value": "source",
        "type": "string",
        "position": 13
      },
      {
        "type": "path",
        "steps": [
          {
            "value": "source",
            "type": "name",
            "position": 22
          }
        ]
      }
    ]
  ]
}

表达式2的AST

{
  "type": "unary",
  "value": "{",
  "position": 1,
  "lhs": [
    [
      {
        "value": "data",
        "type": "string",
        "position": 10
      },
      {
        "type": "unary",
        "value": "{",
        "position": 13,
        "lhs": [
          [
            {
              "value": "email",
              "type": "string",
              "position": 26
            },
            {
              "type": "path",
              "steps": [
                {
                  "value": "data",
                  "type": "name",
                  "position": 33
                },
                {
                  "value": "payload",
                  "type": "name",
                  "position": 41
                },
                {
                  "value": "Email",
                  "type": "name",
                  "position": 47
                }
              ]
            }
          ]
        ]
      }
    ]
  ]
}

组合AST

{
  "type": "unary",
  "value": "{",
  "position": 1,
  "lhs": [
    [
      {
        "value": "source",
        "type": "string",
        "position": 12
      },
      {
        "type": "path",
        "steps": [
          {
            "value": "source",
            "type": "name",
            "position": 20
          }
        ]
      }
    ],
    [
      {
        "value": "data",
        "type": "string",
        "position": 30
      },
      {
        "type": "unary",
        "value": "{",
        "position": 33,
        "lhs": [
          [
            {
              "value": "email",
              "type": "string",
              "position": 46
            },
            {
              "type": "path",
              "steps": [
                {
                  "value": "data",
                  "type": "name",
                  "position": 53
                },
                {
                  "value": "payload",
                  "type": "name",
                  "position": 61
                },
                {
                  "value": "Email",
                  "type": "name",
                  "position": 67
                }
              ]
            }
          ]
        ]
      }
    ]
  ]
}

---

这看起来很有希望。您可以共享自定义序列化程序的代码吗。如果可能，我们可以通过电子邮件进行连接。