18.35What DataWeave syntax should you memorize?

These are enough for your interview:

%dw 2.0
output application/json
---

and:

payload.foo

vars.foo

attributes.foo

payload map (x) -> ...

payload filter (x) -> ...

value default "..."

value as Number

if (...) ... else ...

(field: value) if (...)

array ++ array

object ++ object

If you know those, you can construct most common interview mappings.