Expression error after inner join using join snaps

[Sahil]

Hi,
Getting below expression error in mapper after join snaps:-
Expression worked for 7 previous documengts, but failed on document #8 with the error: $[‘$’] is undefined

[bojanvelevski]

You cannot use that expression. That’ basically means “Get root from root”, or something like that, and is not valid. I know that your field is called “$” so a smart thing to do is first to remap the field.

[del · Accepted solution]

@Sahil,

This error will occur if the key "$" does not exist in your 8th document. You can either:

• change your expression to $.get('$') which will effectively produce a null value for $['$'] downstream
• or if your error is in a Mapper, you can also check the checkbox, which will also produce a null value (but also applies null-safe to all the fields in your mapper).