run time errors -- how to handle?

[dominictarr]

so, using map-reduce again after a while,
got this error. think the key wasn't an array or a string.

what is the best way to handle this error? as a db you might not want it to throw...
probably better that your query does nothing for a bit...

/Users/dominictarr/c/node_modules/map-reduce/index.js:27
            array.push(id)
                  ^
TypeError: Object #<Object> has no method 'push'
    at module.exports.mapper.get.db.get.async (/Users/dominictarr/c/node_modules/map-reduce/index.js:27:19)
    at /Users/dominictarr/c/npmd/db.js:77:3
    at module.exports.acc (/Users/dominictarr/c/node_modules/map-reduce/index.js:23:19)
    at LevelUP.get (/Users/dominictarr/c/npmd/node_modules/levelup/lib/levelup.js:189:13)

I think I'm gonna make it default to [] but leave this issue open incase some one else has ideas.