Looks like Knexjs has specificType, which allows Postgres Array Type . I made it work by adding columnType value as ‘text ARRAY’ in models folder. Just to change the columnType value as valid Postgres type, and you should be good to go.
Example:
"test": {
"columnType": "text ARRAY",
}
This would save the column as test[] in Postgres. I tested it, it works without any issues so far.