readme.md for nodejs developers on windows platform

tests/examples/nodejs/README-win.md

+# 如何在windows上使用nodejs进行TDengine应用开发
+
+
+
+## 环境准备
+
+（1）安装nodejs-10.22.0
+
+下载链接：https://nodejs.org/dist/v10.22.0/node-v10.22.0-win-x64.zip
+
+解压安装：
+
+![image-20201027160836957](C:\Users\Gemini\AppData\Roaming\Typora\typora-user-images\image-20201027160836957.png)
+
+把node配置到环境变量里
+
+![image-20201027161258158](C:\Users\Gemini\AppData\Roaming\Typora\typora-user-images\image-20201027161258158.png)
+
+cmd启动命令行，查看node的版本
+
+```shell
+> node.exe --version
+v10.22.0
+
+> npm --version
+6.14.6
+```
+
+
+
+（2）安装python2.7
+
+下载链接：https://www.python.org/ftp/python/2.7.18/python-2.7.18.amd64.msi
+
+查看python版本
+
+```shell
+>python --version
+Python 2.7.18
+```
+
+
+
+（3）安装TDengine-client
+
+下载地址：https://www.taosdata.com/cn/all-downloads/，选择一个合适的windows-client下载（client应该尽量与server端的版本保持一致）
+
+使用client的taos shell连接server
+
+```shell
+>taos -h node5
+
+Welcome to the TDengine shell from Linux, Client Version:2.0.6.0
+Copyright (c) 2017 by TAOS Data, Inc. All rights reserved.
+
+taos> show dnodes;
+   id   |           end_point            | vnodes | cores  |    status    |  role   |       create_time       |       offline reason       |
+============================================================================================================================================
+      1 | node5:6030                     |      7 |      1 | ready        | any     | 2020-10-26 09:45:26.308 |                            |
+Query OK, 1 row(s) in set (0.036000s)
+```
+
+注意：
+
+* 检查能否在client的机器上ping通server的fqdn
+* 如果你的dns server并没有提供到server的域名解析，可以将server的hostname配置到client的hosts文件中
+
+
+
+## 应用开发
+
+（1）建立nodejs项目
+
+```
+npm init
+```
+
+（2）安装td2.0-connector驱动
+
+``` tdshell
+npm install td2.0-connector
+```
+
+（3）nodejs访问tdengine的示例程序
+
+```javascript
+const taos = require('td2.0-connector');
+
+var host = null;
+var port = 6030;
+for (var i = 2; i < global.process.argv.length; i++) {
+    var key = global.process.argv[i].split("=")[0];
+    var value = global.process.argv[i].split("=")[1];
+
+    if ("host" == key) {
+        host = value;
+    }
+    if ("port" == key) {
+        port = value;
+    }
+}
+
+if (host == null) {
+    console.log("Usage: node nodejsChecker.js host=<hostname> port=<port>");
+    process.exit(0);
+}
+
+// establish connection
+var conn = taos.connect({host: host, user: "root", password: "taosdata", port: port});
+var cursor = conn.cursor();
+// create database
+executeSql("create database if not exists testnodejs", 0);
+// use db
+executeSql("use testnodejs", 0);
+// drop table
+executeSql("drop table if exists testnodejs.weather", 0);
+// create table
+executeSql("create table if not exists testnodejs.weather(ts timestamp, temperature float, humidity int)", 0);
+// insert
+executeSql("insert into testnodejs.weather (ts, temperature, humidity) values(now, 20.5, 34)", 1);
+// select
+executeQuery("select * from testnodejs.weather");
+// close connection
+conn.close();
+
+function executeQuery(sql) {
+    var start = new Date().getTime();
+    var promise = cursor.query(sql, true);
+    var end = new Date().getTime();
+    promise.then(function (result) {
+        printSql(sql, result != null, (end - start));
+        result.pretty();
+    });
+}
+
+function executeSql(sql, affectRows) {
+    var start = new Date().getTime();
+    var promise = cursor.execute(sql);
+    var end = new Date().getTime();
+    printSql(sql, promise == affectRows, (end - start));
+}
+
+function printSql(sql, succeed, cost) {
+    console.log("[ " + (succeed ? "OK" : "ERROR!") + " ] time cost: " + cost + " ms, execute statement ====> " + sql);
+}
+```
+
+（4）测试nodejs程序
+
+```shell
+>node nodejsChecker.js
+Usage: node nodejsChecker.js host=<hostname> port=<port>
+# 提示指定host
+
+>node nodejsChecker.js host=192.168.1.59
+Successfully connected to TDengine
+Query OK, 0 row(s) affected (0.00997610s)
+[ OK ] time cost: 14 ms, execute statement ====> create database if not exists testnodejs
+Query OK, 0 row(s) affected (0.00235920s)
+[ OK ] time cost: 4 ms, execute statement ====> use testnodejs
+Query OK, 0 row(s) affected (0.06604280s)
+[ OK ] time cost: 67 ms, execute statement ====> drop table if exists testnodejs.weather
+Query OK, 0 row(s) affected (0.59403290s)
+[ OK ] time cost: 595 ms, execute statement ====> create table if not exists testnodejs.weather(ts timestamp, temperature float, humidity int)
+Query OK, 1 row(s) affected (0.01058950s)
+[ OK ] time cost: 12 ms, execute statement ====> insert into testnodejs.weather (ts, temperature, humidity) values(now, 20.5, 34)
+Query OK, 1 row(s) in set (0.00401490s)
+[ OK ] time cost: 10 ms, execute statement ====> select * from testnodejs.weather
+Connection is closed
+
+           ts             |       temperature        |  humidity   |
+=====================================================================
+2020-10-27 18:49:15.547   | 20.5                     | 34          |
+```
+