Question

我目前从NodeJS开始，我想使用不同的参数一次多次运行Same函数，但是我不确定如何运行。根据我的当前经验，NodeJS / Javascript通常不会等待函数返回，但是就我而言，它确实让我感到困惑。我当前的代码如下所示：

XMLHttpRequest = require("xmlhttprequest").XMLHttpRequest;
start=function(values){
    max=5
    started=0
    finished=0
    maxReachedBefore=false
    finishedStarting=false
    result=[]

    interval = setInterval(function(){
        if(!finishedStarting){
            if((started-finished)>= max) {
                if(!maxReachedBefore){
                    console.log("Max Reached!")
                    maxReachedBefore=true
                }
                return;
            }
            maxReachedBefore=false
            getValue(values[started])
            console.log("Started getValue")
            started++
        } else {
            if (started<=finished){
                clearInterval(interval)
                console.log("Finished!")
            }
        }

    },10)
}

getValue=function(value){
    var request=new XMLHttpRequest()
    request.open("get","MY_WEBSITE_HERE.COM/"+value, false)
    request.send()
    result=result.concat(request.responseText)
    console.log("Finished getValue")
    finished++
}

start(["a","medium","sized","list","of","values","that","i","want","to","get","the","corresponding","values","to"])

现在，我希望这会在未达到最大值的情况下以不同的值保持启动getValue-> getValue运行少于6次，但这不是这种情况。 getValue逐个启动，下一个仅在最后一个完成后才开始。有人可以解释为什么会这样/帮助我更改它吗？

[请留意，对于NodeJS来说还比较陌生]

Answer 1

您正在向服务器发送同步请求。因此该功能将等待服务器的响应。

boolean

最后一个参数request.open("get","MY_WEBSITE_HERE.COM/"+value, true)指定呼叫是同步还是异步。

var finished = 0;
var result=[];
 start=function(values){
 max=5
 started=0    
 maxReachedBefore=false
 finishedStarting=false

  interval = setInterval(function(){
    if(!finishedStarting){
        if((started-finished)>= max) {
            if(!maxReachedBefore){
                console.log("Max Reached!")
                maxReachedBefore=true; 
                finishedStarting = true;
            }
            return;
        }
        maxReachedBefore=false; 
        console.log("Started getValue " + values[started]);

        getValue(values[started]); 
        started++;

    } else {
        if (started<=finished){
            clearInterval(interval)
            console.log("Finished!")
        }
    }

  },10);
}

getValue=function(value){
    var request=new XMLHttpRequest()
    request.open("get","MY_WEBSITE_HERE.COM/"+value, true); 

    request.onreadystatechange = function () {
     if(request.readyState === 4 && request.status === 200) {
       result=result.concat(request.responseText);
       console.log("Finished getValue " + value)
       finished++;
     }
    };
   request.send();
   console.log("request sent");
}

这将发送异步调用，并在回调函数中添加完成获取值的控制台语句。

 !define MUI_DEFAULT_MUI_WELCOMEFINISHPAGE_BITMAP "E:\Code\PCPE\NULLSOFT\src\Bitmaps\dlgbmp-for-china.bmp"

NodeJS：不要等待函数返回

1 个答案: