Replace Nest Key

[ruiminhu]

Hey @repeatedly , I want to redact my value, the key is nested.
However, just some record has both 2 level of nested keys.
{
"properties": {
"messageTracingId": 12345,
"connectionId": "ABCDE",
"traceId": "akhsb:01",
"hub": "chatsamplehub",
"userId": "eyJAdlhopWkXY.eyJuKXE4gp4QP.hlGrujNIvT"
},
"resourceId": "balabal",
"time": "2023-07-10T10:45:29Z"
}

I want to replace value of the [properties][userId], if it's pattern match. But not every record has properties and not each properties has userId.
How should I check before I do the following?

filter mdsdlog.asrs.customer>
@type record_modifier

expression /(?-i)eyJ(?i)[a-z0-9\-_%]+\.(?-i)eyJ(?i)[a-z0-9\-_%]+\.[a-z0-9\-_%]+/ key **$.properties.userId** replace "[REDACTED]"