Nodejs学习

学习基础：Node.js Express TypeScript Mongodb；

1.Nodejs

1.回调函数:回调函数就是一个通过[函数指针](https://baike.baidu.com/item/%E5%87%BD%E6%95%B0%E6%8C%87%E9%92%88/2674905)调用的函数
function callBackfnc(fnc){
    fnc();
}
function sayHello(){
    console.log("Hello")
}
callBackfnc(sayHello);

2.文件读写:
var fs = require("fs");

// readFileSync:同步执行
// var readMe = fs.readFileSync("ReadMe.text","utf-8");
// 异步执行
fs.readFile("ReadMe.text","utf-8",function(err,data){
    console.log("data",data)
});
console.log("readme")


// 新建文件夹
fs.mkdir("stuff",function(){
    // 读取文件
    fs.readFile("ReadMe.text","utf-8",function(err,data){
        // 写入内容
        fs.writeFile("./stuff/copyStuff.text",data,function(){
            console.log("Write Success")
        })
    })
})

3.流
var fs = require("fs");

// 读取流
var myReadStream = fs.createReadStream(__dirname+"/ReadMe.text","utf-8");
// 写入流
var myWriteStream = fs.createWriteStream(__dirname+"/WriteMe.text","utf-8");

myWriteStream.write("测试数据111","utf-8");
myWriteStream.end();
myWriteStream.on("finish",function(){
    console.log("Write Success")
})


// var str = "";
// //接收数据的监听函数
// myReadStream.on("data",function(chunk){
//     str+= chunk;
//     // console.log("chunk",chunk)
//     // 写入
//     myWriteStream.write(chunk);
// })

// // 读取结束监听事件
// myReadStream.on("end",function(){
//     console.log("str",str)
// })

4.服务器
var http = require("http");
var fs = require("fs");

var myReadStream = fs.createReadStream(__dirname + "/index.html", "utf-8")

function startServer() {
    var server = http.createServer(function (req, res) {
        var url = req.url;
        switch (url) {
            case "/plain":
                res.writeHead(200, {
                    "Content-type": "text/plain"
                });
                res.write("Hey I Got It");
                res.end();
                break;
            case "/json":
                res.writeHead(200, {
                    "Content-type": "application/json"
                });
                var myJson = {
                    name: "zpwan",
                    age: "18",
                    date: new Date()
                };
                res.end(JSON.stringify(myJson));
                break;
            case "/html":
                res.writeHead(200, {
                    "Content-type": "text/html"
                });
                myReadStream.pipe(res);
                break;
            default:
                break;
        }
    })
    server.listen(2828);
    console.log("Server Start on 127.0.0.1:2828")
}
module.exports.startServer = startServer

startserver.js:

var startServer = require("./request");
startServer.startServer();