log4js

<!-- 以下是基于 Koa 的案列 -->
const log4js = require("log4js")
log4js.configure({
  appenders: { cheese: { type: "file", filename: "cheese.log" } },
  categories: { default: { appenders: ["cheese"], level: "error" } }
})

const logger = log4js.getLogger("cheese")
logger.trace("Entering cheese testing")
logger.debug("Got cheese.")
logger.info("Cheese is Comté.")
logger.warn("Cheese is quite smelly.")
logger.error("Cheese is too ripe!")
logger.fatal("Cheese was breeding ground for listeria.")