Change log level from number to log name #83

When I try to print the below log, it prints "level" in numbers. Instead, I want it in the log level name itself.
logger.info('Information!') {"name":"main","hostname":"mint","pid":14607,"level":30,"time":"2016-10-16T22:26:48.835+09:00","v":0,"msg":"Information!"}

Am expecting,

logger.info('Information!') {"name":"main","hostname":"mint","pid":14607,"level":"Info","time":"2016-10-16T22:26:48.835+09:00","v":0,"msg":"Information!"}
How to do this?