Executive Sub-workflow node

Questions
1

Hi, everyone . A friend of mine introduced me to this forum saying i can get help for my n8n problem.

i’m having an issue with an executive sub-workflow node.

i’m passing a few values from the previous node into the sub-workfow, but n8n keeps complaining about one of the inputs . the workflow runs fine until it reaches the sub-workflow.

the confusing part is that the value looks correct in the previous node.

please i need help and i am runing out of time.

2

@Chuks_Saint Welcome!.

Yes your friend was right this community is to help get your issues solved when working with n8n .. and we have several professional supporters here for that .

can you share a screenshot of the Execute Sub-workflow node with the workflow inputs visible?

Also , what type is the problematic input supposed to be… strings , number, boolean , or array?

And if possible , expand the input data from the previous node so we can compare the actual value with what you are passing into the sub-workflow.

3

sure , i have shared my screen below .

the error is showing on the fieldList. with :
“clientId, status, createdAt”
and the error :
Invalid value: Expected Array, received string

n8n222
n8n2221179×679 598 KB

4

@Chuks_Saint after checking carefully…I found the issue .

your fieldsList input is configured as an array , but you’re passing it as a single string:

“clientId, status, createdAt”
so n8n is receiving:

JSON
{
"fieldsList":  "clientId, status, createdAt"
}

instead of

JSON
{
"fieldsList" : [
"clientId",
"status",
"createdAt"
]
}

change the expression/value going into fieldsList so it returns an actual array.
For example ,if the previous node contains the comma-separated value, you can use:

{{$json.fieldsList.split(',')}}

or , if you already have fields as an array upstream , pass that array directly rather than converting it to a string .

n8n’s data-mapping docs explain that expressions can be used to reference and pass data from previous nodes , so the important thing here is that the data type of the expression matches the parameter type .

please check the n8n docs for reference

5

Ah, i see now .

i was joining the fields into a string ealier and then passing that value directly into the sub-workflow.

changed it to {{$json.fieldList.split(’ ')}} and the validation error is gone. The sub-workflow is runing now thanks a lot !

6

Hi @Chuks_Saint Welcome!
The joined string in your screenshot is “clientId,status,createdAt”, and split(’ ') on a comma joined string does not separate the names, it returns one element or leaves commas stuck to them. That still passes the array check, so the sub-workflow gets wrong field names. Split on the comma and trim the spaces:

{{ $json.fieldList.split(',').map(f => f.trim()) }}

Please also consider marking the reply that fixed it as the solution, it helps future readers find what actually worked.

7

nice :+1: please don’t forget to hit the solution button so as to help others that have the same issues