等哪天需要引入日志组件来代替console.log的时候，才发现恶梦开始了。
遇到这种情况有没有什么好的办法呢，本文提供一个思路：将console.log这些方法重写。
以winston日志组件为例：
const util = require('node:util')
function formatArgs(func){
return function (...theArgs) {
const formatString = theArgs[0]
const args = theArgs.slice(1)
func?.(util.format(formatString, ...args))
}
}
// logger 为 winston实例
function bindToConsole(logger){
console.log = formatArgs(logger.info.bind(logger))
console.error = formatArgs(logger.error.bind(logger))
console.info = formatArgs(logger.info.bind(logger))
}
这样就达到了重写console方法的目的，bindToConsole(logger)之后的代码中的console.log, console.error, console.info都会调用winston logger中相应的方法进行日志打印或保存。其它日志组件也可以参考此方法。附完整代码：
const util = require('node:util')
const winston = require('winston')
const DailyRotateFile = require('winston-daily-rotate-file')
const _createLogger = winston.createLogger
const format = winston.format
const transports = winston.transports
const customFormat = format.combine(
format.timestamp({format: 'YYYY-MM-DD HH:mm:ss'}),
format.align(),
format.printf((i) => `${i.level}: [${i.timestamp}]: ${i.message}`)
)
const defaultOptions = {
format: customFormat,
datePattern: "YYYY-MM-DD",
zippedArchive: true,
maxSize: "20m",
maxFiles: "90d"
}
function formatArgs(func){
return function (...theArgs) {
const formatString = theArgs[0]
const args = theArgs.slice(1)
func?.(util.format(formatString, ...args))
}
}
function bindToConsole(logger){
console.log = formatArgs(logger.info.bind(logger))
console.error = formatArgs(logger.error.bind(logger))
console.info = formatArgs(logger.info.bind(logger))
}
function createLogger(dir){
const logger = _createLogger({
format: customFormat,
transports: [
new transports.Console(),
new DailyRotateFile({
filename: dir+"/%DATE%.log",
level: "info",
...defaultOptions
}),
new transports.File({
filename: "logs/error.log",
level: "error"
})
]
})
bindToConsole(logger)
return logger
}
module.exports = {
createLogger
}