Javascript 需要解释node.js npm（express）吗？

请给我解释一下这条线是怎么工作的

app.get("/speak/:animal", function(req, res) {
    var sounds = {
        pig: "OINK",
        cow: "MOO",
        dog: "WOOF WOOF",
        cat: "I hate humans",
        goldfish: "..."
    };

    var animal = req.params.animal.toLowerCase();
    var sound = sounds[animal];
    res.send("The " + animal + " says '" + sound + "'");
});

还有这条线

app.get("/repeat/:message/:times", function(req, res) {
    var message = req.params.message;
    var times = Number(req.params.times);
    var result = "";
    for(var i = 0; i < times; i++) {
        result += message + " ";
    }

    res.send(result);
});

app.get（“/repeat/：message/：times”），函数（req，res）{
var message=req.params.message；
var时间=数量（要求参数时间）；
var结果=”；
对于（变量i=0；i<次；i++）{
结果+=消息+“”；
}
res.send（结果）；
});

第一个：

  // Listens to all the get requests on the url path /speak/anything 
  // :animal is a placeholder, anything you pass in the url will be be available in the url param animal.
     app.get("/speak/:animal", function(req, res){
          // JSON object with a key value pair.
           var sounds = {
           pig: "OINK",
           cow: "MOO",
           dog: "WOOF WOOF",
           cat: "I hate humans",
           goldfish: "..."
       };
           // Converts the request parameter 'anything' in the url to a lower case string.
           var animal = req.params.animal.toLowerCase();
           // Tries to find the sound in the sounds object since 'anything' is no key it wont find a suitable value for the sound.
           var sound = sounds[animal];
           // Responds to the request with the resolved sound.
           res.send("The " + animal + " says '" + sound + "'");

第二个

// Let us consider that the request /repeat/received/10
     app.get("/repeat/:message/:times", function(req, res){
      // the  /received in the url will be available to access under the req.param.messages
       var message = req.params.message;
       // message = received 
       // Converting the times string 10 passed in the url to a number
       var times = Number(req.params.times);
       var result = "";
       // loop will run from 0 to 9 and keep appending to the string result
       for(var i = 0; i < times; i++){
           result += message + " ";
       }
       // At the end of the for loop
       // result will contain = 'received received received' 7 more time ...
       // will send the response to the request.
       res.send(result);

    });

<代码> /让我们考虑请求/重复/接收/ 10 app.get（“/repeat/：message/：times”），函数（req，res）{ //url中接收的/将可在req.param.messages下访问 var message=req.params.message； //消息=已收到 //将url中传递的时间字符串10转换为数字 var时间=数量（要求参数时间）； var结果=”； //循环将从0运行到9，并继续追加到字符串结果 对于（变量i=0；i<次；i++）{ 结果+=消息+“”； } //在for循环的末尾 //结果将包含='received'7更多时间。。。 //将发送对请求的响应。 res.send（结果）； });

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1。“汪汪”2。是express.js：哪一行？您在理解什么方面有困难？var animal=req.params.animal///这意味着，在发出get请求时，会在url中为动物传递一个动态值，例如/speak/cat，以了解在url中访问的是哪种资源，您可以使用req.param.animal访问它，在本例中返回cat。