======版本升级======
先清除 npm cache npm cache clean -f

安装n模块 npm install -g n

然后就可以开始升级了：自动安装到最新的稳定版本命令是 n stable，自由选择版本安装是n 4.4.0（版本号）

备注：升级前后可先使用node -v 查看版本。查看所有node版本是n ls

======链接Oracle======
npm i oracledb

下载安装Oracle Client：
https://www.oracle.com/database/technologies/instant-client/downloads.html

<code javascript>
var oracledb = require("oracledb");
(async ()=>{
	try{
		await oracledb.createPool({
		        _enableStats: true,
		        user: 'xxxxx',
		        password: 'xxxxx',
		        connectString: 'IP:PORT/orcl',
		        poolAlias: "pangxiepool"
	      });
	     var connection =  await oracledb.getPool('pangxiepool').getConnection();
	console.log('connection');
console.log(connection);
	     var result = await connection.execute('select * from EZR_TRANS WHERE rownum<10');
console.log('result');
console.log(result);
	     await connection.close();
	     console.log(result)
	}catch(err){
	    console.log(err.message)
	}
})();
</code>

======跨域======
<code bash>
$ npm install cors
</code>
Usage
Simple Usage (Enable All CORS Requests)
<code JavaScript>
var express = require('express')
var cors = require('cors')
var app = express()

app.use(cors())

app.get('/products/:id', function (req, res, next) {
  res.json({msg: 'This is CORS-enabled for all origins!'})
})

app.listen(80, function () {
  console.log('CORS-enabled web server listening on port 80')
})
</code>

======安全证书======
<code JavaScript>
var oracledb = require("oracledb");
var express = require('express')
var cors = require('cors')
var https = require('https')
var http = require('http')
var server = express()
var fs = require('fs')
//使用跨域中间件
server.use(cors());
var options = {
	key: fs.readFileSync('./biapi.re-blue.com.key'),
	cert: fs.readFileSync('./biapi.re-blue.com.pem'),
}
console.log(options)
http.createServer(server).listen(80);
https.createServer(options, server).listen(443);
console.log('启动成功...')
</code>
======相关概念======
  * [[https://www.jianshu.com/p/db31116e6d71|异步处理的演进]]
  * [[https://www.jianshu.com/p/0837dde8dcd5|使用 Async/Await]]