Troubleshooting JSONata transform error: "Cannot convert undefined or null to object"

Applies to: Turbine Cloud 26.4.1 (JSONata 2.2.1)

Overview

A playbook or component may fail in a Transform Data action with this JSONata error:

Cannot convert undefined or null to object

This usually means a transform expression is referencing a field or property that is not present in the input data for that run. Turbine Cloud 26.4.1 uses JSONata 2.2.1, which evaluates these cases more strictly than earlier JSONata versions.

In earlier releases, an invalid property path could resolve to empty or undefined output without failing the transform block. With JSONata 2.2.1, expressions that pass undefined or null into object functions (such as $sift()) are more likely to fail the block and stop the playbook run.

This is not a universal change to Transform output structure. In most reported cases, the expression itself references an invalid path that previously may not have caused the block to fail.

Symptoms

You may see:

A playbook or component run fails in a Transform action (commonly seen on 26.4.1 with JSONata 2.2.1)

Failure occurs in a Transform Data / JSONata action

Error message:

Cannot convert undefined or null to object

The error may also include:

the transform block name (for example, data)

a position number in the expression

What to check

Confirm your tenant is on 26.4.1 (JSONata 2.2.1)

Open the failed playbook run and identify:

the failing action

the transform block name

the exact error message

Review the transform expression against the actual input payload from the failed run

Look for references to properties or paths that do not exist in the input JSON

If the expression assumes a nested object exists, but the payload contains null or a missing field, the transform may fail under JSONata 2.2.1.

If your error looks different

The same error message can have different root causes. Not every Cannot convert undefined or null to object failure has the same fix.

If your failure does not match a known pattern below, contact Swimlane Support and provide:

tenant URL / region

Turbine version (26.4.1)

playbook or component name

failing action and transform block name

run ID and job ID

screenshot or export of the failing transform expression

time the failure started

Support will review the expression against the actual run input and advise on the correct fix.

Known example: email ingestion (Process Graph API Email)

We have also seen this error in email ingestion workflows using the component below. Include this section only if your failure matches this pattern.

Component

Process Graph API Email

Failing location

Item	Value
Action	Parse Attachment Fields
Transform block	data

Cause

The transform expression may reference an invalid property path such as:

$sift(loops.Foreach_Attachment.value.attacment.info, function($v, $k) { $k != "contentBytes"})

The attachment data is structured as:

{
  "info": { ... },
  "data": [ ... ]
}

Because attacment is not a valid property, the expression fails under JSONata 2.2.1.

Resolution

Update the expression in block data to:

$sift(loops.Foreach_Attachment.value.info, function($v, $k) { $k != "contentBytes"})

Steps

Open the Process Graph API Email component

Go to Parse Attachment Fields

Edit transform block data

Update the expression as shown above

Save the component

Re-run the workflow and confirm the playbook completes successfully

Short summary

Some Transform actions may fail with "Cannot convert undefined or null to object" when JSONata 2.2.1 evaluates an invalid property path more strictly than earlier versions. Review the failing expression against the run input payload. One known example affects email ingestion via Process Graph API Email → Parse Attachment Fields → block data. Contact Support if your case does not match or you need help validating the fix.

Need more help?

Open a support ticket with your run details and reference this article. Our team can help confirm whether your case matches a known pattern or needs further investigation.