ServiceNow Transform Scripts: Map Source Data

ServiceNow Import & transform scripts

Shape and clean incoming data as it flows from an import set into target tables.

Quick answer

Transform scripts run inside a transform map at five events: onStart before any rows, onBefore and onAfter around each row, onComplete at the end and onForeignInsert when a referenced record must be created. In onBefore, source is the import-set row and target the record being written; set ignore to skip a row or error to reject it.

Key takeaways

The transform events
An onBefore script
Coalesce and field maps
Try it Yourself

When you load data with import sets and transform maps, transform scripts are the code hooks that let you clean, enrich and control each row as it is written to the target table. They turn a dumb column-to-column map into a smart, defensible data pipeline.

The transform events

onStart

Once, before any rows, set up counters or lookups.

onBefore

Per row, before insert/update, clean or default fields.

onAfter

Per row, after the write, create related records.

onComplete

Once, at the end, log a summary.

onForeignInsert

When a referenced record must be created.

An onBefore script

// Normalise email and skip blank rows
(function transformRow(source, target, map, log, isUpdate) {
  if (source.u_email.nil()) {
    ignore = true;   // skip this row
    return;
  }
  target.email = source.u_email.toString().toLowerCase();
})(source, target, map, log, action==="update");

source, target and the ignore flag. source is the import-set row, target is the record being written. Set ignore = true in onBefore to skip a row, and use error = true with a log message to reject bad data instead of silently corrupting the target table.

Coalesce and field maps

A coalesce field decides insert-vs-update (match found = update). Prefer field maps and coalesce for the simple stuff; reserve scripts for transformations the mapping UI can't express.

Try it YourselfJavaScript

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Runs in a sandbox in your browser. Mock gs and GlideRecord and sample data are provided.