format.md

Format

Format property can be a string template or a function

Template

Example: '[{h}:{i}:{s}.{ms}] [{level}] {text}'

Name	Value
level	Logging level
text	Serialized log message
processType	browser or renderer
y	Year
m	Month
d	Day
h	Hour
i	Minute
s	Second
ms	Millisecond
z	Timezone offset
iso	date.toISOString()

Also, you can use your own values:

log.variables.label = 'dev';
log.transports.console.format = '[{h}:{i}:{s}.{ms}] [{label}] {text}';

Function

(message: LogMessage) => string

log.transports.console.format = (message) => {
  return util.format.apply(util, message.data);
}