Show undefined results in fetch preview window

[Janpot]

Duplicates

• I have searched the existing issues

Latest version

• I have tested the latest version

Current behavior 😯

User specifies a function body without a return statement. e.g.

'hello';

or a non existing property:

return hello.idontexist

currently the preview window stays empty

Expected behavior 🤔

it shows undefined

Steps to reproduce 🕹

Steps:

1. create query
2. enable transforn
3. add function body: return;
4. press "preview"

Context 🔦

Additionally to enlarge the pit of success we could add

• a short helper text + link to docs about what sort of code should be entered in the transform editor
• an info message when the preview returns undefined that asks the user whether they perhaps forgot a return statement, or are accessing a non-existing property. We should probably not make this an error as there may be valid use-cases

Your environment 🌎

No response