Export Transformation Codes are the second way to perform custom transformations in evaluations. In this case, they are used to output data for an export in any desired format. The input format, like with Chart Transformation Codes, is the result of the SQL evaluation, with an array of objects:

[
  {
    "Probe": "P01",
    "Messwert": 0.31
  }, {
    "Probe": "P02",
    "Messwert": 1.54
  }
]

The return value must be a string in this case, as the result is no longer processed further on the server side. Here is an example of a simple transformation into a CSV format.

function transform (data) {
  let csv = Object.keys(data[0]).join(';') + '\n'
  
  csv += data.map(row => {
    return Object.keys(row).map(k => row[k]).join(';')
  }).join('\n')
  
  return csv
}

Continue with: Webservice Response Handler