回调中的NodeJS Local变量 [英] NodeJS Local variable in callback

问题描述

我，
我知道，关于SO的信息很多，但是我找不到适合我情况的正确答案。

I, I know, there is a lot information about this on SO, but I didn't find the right answer for my situation.

我有这段代码：

for(var i=0; i < shop.collections.length; i++){
  if(!shop.collection[i].active){
    var data = {
      name: shop.collection[i].name,
      visible: true
    };

    myOwnService.createCollection(data, accessToken, function(err, response, body){
      shop.collections[i].serviceId = body.id;
  })
}

我的问题是商店在 myOwnService.createCollection（）服务中未定义。在回调中访问 shop 变量的正确方法是什么，那么如何更新对象以便保存结果？

My problem is that shop is undefined in the myOwnService.createCollection() service. What is the right way to access the shop variable in the callback, so how I can update the object so I can save the result?

推荐答案

shop 在 myOwnService.createCollection

shop is in the parent scope of the myOwnService.createCollection function hence it is accessible inside it.

上面代码中唯一的问题是 i c $ c> callback 始终是最后一个值，因为它将在事件循环后执行。

Only issue in above code is i used in callback which will always be the last value as it will be executed after event loop.

使用围绕 myOwnService.createCollection 的I​​IFE 包装器，以便可以传递 i 的范围。

Use IIFE wrapper around myOwnService.createCollection so that scope of i could be passed.

for (var i = 0; i < shop.collections.length; i++) {
  if (!shop.collection[i].active) {
    var data = {
      name: shop.collection[i].name,
      visible: true
    };
    (function(i) {
      myOwnService.createCollection(data, accessToken, function(err, response, body) {
        shop.collections[i].serviceId = body.id;
      });
    })(i);
  }
}

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