[Feature Request]: Enhance Concat Fields to Support Skipping Null Values #6433
Description
What would you like to happen?
[Feature Request] Concat Fields: Option to Skip Null Values
Summary
Enhance the Concat Fields transform to optionally skip null field values when concatenating multiple input fields using a delimiter.
Problem Statement
The current Concat Fields transform concatenates all configured fields regardless of whether individual values are null.
When one or more fields are null, the output contains empty values and extra delimiters, which then require additional transforms or scripting to clean up. (e.g. to create a well formed address)
This is a common scenario when working with partially populated records from upstream systems.
Proposed Behaviour
When enabled, the transform should:
- Ignore
nullinput values - Concatenate only fields that contain values
- Apply delimiters only between existing values
Examples
Configured fields: a, b, c
Delimiter: ,
| a | b | c | Current Output | Proposed Output |
|---|---|---|---|---|
| a | b | c | a,b,c | a,b,c |
| a | b | null | a ,b, | a,b |
| a | null | null | a,, | a |
| null | b | c | ,b,c | b,c |
| null | b | null | ,b, | b |
| null | null | c | ,,c | c |
| null | null | null | ,, | null |
Suggested UI / Configuration
Add an optional flag to the Concat Fields transform configuration, for example:
- Skip null values (optional)
- Skip empty strings (optional)
When disabled, the transform behaves exactly as it does today.
Benefits
- Eliminates the need for downstream cleanup logic
- Reduces reliance on User Defined Java Expression or JavaScript transforms
- Produces cleaner and more predictable output
- Matches common expectations for string concatenation in data integration workflows
Backward Compatibility
- Feature is opt-in
- Existing pipelines are unaffected unless explicitly enabled
Issue Priority
Priority: 3
Issue Component
Component: Hop Gui