Javascript OOP从函数返回值 [英] Javascript OOP return value from function

问题描述

  function SocialMiner（）
 {
 
 
 var verbose = true; 
 
 var profileArray = new Array（）; 
 
 var tabUrl; 
 
 this.getTabUrl = function（）
 {
 logToConsole（getTabUrl is called）; 
 
 
 chrome.tabs.getSelected（null，function（tab）
 {
 tabUrl = tab.url; 
 logToConsole（tabUrl）; 
 
}）; 
 
返回tabUrl; 
}`
  

然后我在SocialMiner ojbect上调用这个函数：

  var pageUrl = miner.getTabUrl（）; 
 miner.logToConsole（pageUrl）; 
  

第一次调用 logToConsole 成功打印Url，而第二个说未定义。我是不是从函数返回相同的值？

更新：这是我如何定义logToConsole：

<$ （文本）
{
if（verbose）
console.log（text）; pre $
}

this.logToConsole = logToConsole;


解决方案

在第二个示例中，您正在调用logToConsole，它是矿工对象的一个​​功能，不是。

  miner.logToConsole 
 
  this.logToConsole = function（text）
 {
 if（verbose）
 console.log（text）; 
} 
  
 
I have javascript object defined like this:
function SocialMiner() 
{


var verbose=true;

var profileArray=new Array();

var tabUrl;

this.getTabUrl=function()
{
    logToConsole("getTabUrl is called");


    chrome.tabs.getSelected(null, function(tab)
    {
        tabUrl = tab.url;
        logToConsole(tabUrl);

    });

    return tabUrl;
}   `
Then I call this function on SocialMiner ojbect like this:
 var pageUrl=miner.getTabUrl();
 miner.logToConsole(pageUrl);
What is the reason that first call to logToConsole successfully prints the Url, while second one says undefined. Am I not returning the same value from the function ?

Update: This is how I have defined logToConsole:
function logToConsole(text) 
    {
        if (verbose)
            console.log(text);
    }

    this.logToConsole=logToConsole;

解决方案
In the second example, you are calling logToConsole as if it is a function of the miner object, which is is not.
miner.logToConsole
Edit 

Per comments about github example, this should make the logToConsole function par of the SocialMiner object.  However, I didn't read the class thoroughly, so proceed with caution with regards to how it is intended to be used.
this.logToConsole=function(text) 
{
    if (verbose)
        console.log(text);
}


                        
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