[JavaScript知识库]log4js 封装

log4js是js的log工具

本身比较好用，简易做了下封装

1.定义一个普通的console的日志输出 和文件的保存输出（默认error级别） 导出一个定义函数

utils/log4js.js

const log4js = require('log4js')

const levels = {
    'trace': log4js.levels.TRACE,
    'debug': log4js.levels.DEBUG,
    'info': log4js.levels.INFO,
    'warn': log4js.levels.WARN,
    'error': log4js.levels.ERROR,
    'fatal': log4js.levels.FATAL,
}

log4js.configure({
    appenders: {
        console: {type: 'console'},
        error: {
            type: "dateFile",
            filename: 'logs/error-log',
            pattern: 'yyyy-MM-dd.log',
            alwaysIncludePattern: true
        }
    },
    categories: {
        // 默认的 getLogger
        default: {appenders: ['console'], level: 'debug'},
        error: {
            appenders: ['error'],
            level: 'error'
        }
    }
})

function defineLogger(type = 'default') {
    const obj = {}
    Object.keys(levels).forEach(key => {
        obj[key] = (c) => {
            const log = log4js.getLogger(type);
            log.level = levels[key]
            log[key](c)
        }
    })
    return obj
}

module.exports = defineLogger

2.使用

app.js

导入 定义

const defineLogger = require('./utils/log4js')
const defaultLogger = defineLogger()
const errorLogger = defineLogger("error")


// logger
app.use(async (ctx, next) => {
  await next()
  defaultLogger.fatal("this is default fatal console log")
  errorLogger.fatal("this is error fatal in file")
})

似乎需要自己创建logs文件夹