Forum Discussion

spinaka's avatar
spinaka
New Contributor III
4 years ago

Mapping the columns matching from the Array

Hello SnapLogic Experts, I require your help in mapping expression to map the keys(columns). I need to change the column names in the incoming data according to the mapping list that I have and l...
expression_language
transform
viktor_n's avatar
viktor_n
Contributor II
4 years ago

Hi @spinaka,

I do not understand the “Column mapping data from parameter”. You are sending this array as parameter in the pipeline or something ?

Here is a solution that might help you, if it’s not correct just answer me question above.

My sample data for the expression:

[
  {
  "ID":1,
  "NAME":"testuser",
  "Mapping": [
      {
      "src_col_name": "ID",
      "tgt_col_name": "sys_id"
      },
      {
      "src_col_name": "NAME",
      "tgt_col_name": "user_name"
      }
    ]
  }
]

Expression:
$.mapKeys((value, key) => $Mapping.findIndex(el => el.src_col_name == key) >= 0 ? $Mapping.find(element => element.src_col_name == key).tgt_col_name : key)

Output:

[
  {
    "sys_id": 1,
    "user_name": "testuser"
  }
]

Regards.
Viktor

  • spinaka's avatar
    spinaka
    New Contributor III
    4 years ago

    Amazing @viktor_n. I made a little change and your trick worked perfectly. You deserve an award 🙂

    I will be using it in my original pipeline to see the same result. Would mind clarifying the “findIndex()” used here?

    I transformed the column mapping accordingly. Not an issue.

    • viktor_n's avatar
      viktor_n
      Contributor II
      4 years ago

      findIndex() function is used for searching the index of a particular element in Array. If match is not found, -1 is returned.

      Syntax: { Array }.findIndex(((element, index, array) => { condition })
      Accepts a callback function that returns 3 parameters.

      • First parameter is the value of each element
      • Second is the index
      • Third is the original array.

      The returned index is the index of the first element that returns true.

      $Mapping.findIndex(el => el.src_col_name == key)

      Here inside the expression I check if the ‘Mapping’ array has ‘src_col_name’ with a value same as the field from the root($), and if it finds a match it will return the index of that particular element, otherwise it will be -1.

      Hope this will help you