An implementation of log files in nodeJS

First use the nodeJS standard file system module FS:

const fs = require('fs');
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Logs are usually time-stamped, so import the timestamp tool:

const dateTime = require('node-datetime');
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Write to the log file of this article according to different log levels:

var log = {
  setName:function(message) {
    logName = message;
  },
  all:function(message){
    console.log(getDate() + ' [ ALL - '+prepareLogName()+'] '+ message);
    writeMessage(getDate() + ' [ ALL - '+prepareLogName()+'] '+ message);
  },
  trace:function(message){
    console.log(getDate() + ' [ TRACE - '+prepareLogName()+'] '+ message);
    writeMessage(getDate() + ' [ TRACE - '+prepareLogName()+'] '+ message);
  },
  debug:function(message){
    console.log(getDate() + ' [ DEBUG - '+prepareLogName()+'] '+ message);
    writeMessage(getDate() + ' [ DEBUG - '+prepareLogName()+'] '+ message);
  },
  info:function(message){
    debugger;
    console.log(getDate() + ' [ INFO - '+prepareLogName()+'] '+ message);
    writeMessage(getDate() + ' [ INFO - '+prepareLogName()+'] '+ message);
  },
  warn:function(message){
    console.log(getDate() + ' [ WARN - '+prepareLogName()+'] '+ message);
    writeMessage(getDate() + ' [ WARN - '+prepareLogName()+'] '+ message);
  },
  error:function(message){
    console.log(getDate() + ' [ ERROR - '+prepareLogName()+'] '+ message);
    writeMessage(getDate() + ' [ ERROR - '+prepareLogName()+'] '+ message);
  },
  fatal:function(message){
    console.log(getDate() + ' [ FATAL - '+prepareLogName()+'] '+ message);
    writeMessage(getDate() + ' [ FATAL - '+prepareLogName()+'] '+ message);
  },
  off:function(message){
    console.log(getDate() + ' [ OFF - '+prepareLogName()+'] '+ message);
    writeMessage(getDate() + ' [ OFF - '+prepareLogName()+'] '+ message); }}Copy the code

The writeMessage method is implemented by calling fs to write to the local log file synchronously:

function writeMessage(message) {
		pwd = process.cwd();
		fs.appendFileSync(pwd+'/logs/log', message+"\n");
}
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The last local log file to be written is shown below:

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