nodejs渐入佳境[3]-require导入模块

console.log('start nodes.js');

//打印字符串
console.log('Start app.');

const nodes = require('./nodes.js')
//导入node自带modules，fs文件操作
const fs = require('fs');
//os系统操作
const os = require('os');
//获取系统名字
var user = os.userInfo();

//添加字符串到回调函数中，并执行回调函数。出错就会报错，不出错就会打印出'The "data to append" was appended to file!'
fs.appendFile('greetings.txt',`Hello ${user.username}`,(err) => {
  if (err) throw err;
  console.log('The "data to append" was appended to file!');
}
);

> node app.js

Start app.
start nodes.js
The "data to append" was appended to file!

console.log('start nodes.js');

module.exports.age = 25;

//打印字符串
console.log('Start app.');

const nodes = require('./nodes.js')
//导入node自带modules，fs文件操作
const fs = require('fs');
//os系统操作
const os = require('os');
//获取系统名字
var user = os.userInfo();

//添加字符串到回调函数中，并执行回调函数。出错就会报错，不出错就会打印出'The "data to append" was appended to file!'
fs.appendFile('greetings.txt',`Hello ${user.username} age ${nodes.age}`,(err) => {
  if (err) throw err;
  console.log('The "data to append" was appended to file!');
}
);

> node app.js

console.log('start nodes.js');

module.exports.addNote = ()=>{
  console.log('addNode');
  return 'New Node';
};

console.log('Start app.');

const nodes = require('./nodes.js')

 const res = nodes.addNote();
console.log(res);

> node app.js

Start app.
start nodes.js
addNode
New Node

console.log('start nodes.js');

module.exports.add = (a,b)=>{

  return a+b;
};

module.exports.addNote = ()=>{
  console.log('addNode');
  return 'New Node';
};

//打印字符串
console.log('Start app.');

const nodes = require('./nodes.js')

 const res = nodes.add(1,2);
console.log(res);

> node app.js

Start app.
start nodes.js
3