Javascript 向数组中的对象追加新元素

我已经对这个循环困惑了几天，不能完全达到我所需要的

我循环搜索结果数组mdb_results，并从每个对象中提取一个.name作为Google CSE图像搜索中的_搜索词

Th CSE返回另一个数组CSE，我想将其附加到从中提取_搜索词mdb_results[I]的对象

我正在努力实现这样的目标

[{"name":"FOO", 
  "images":[{"img1":"http://thumbnail1"},{"img2":"http://thumbnail2"}]
},
{"name":"FOOOO", 
  "images":[{"img1":"http://thumbnaila"},{"img2":"http://thumbnailb"}]
}]

有人能告诉我如何做到这一点吗

---

谢谢

问题在于您希望异步操作同步工作：

router.get('/json', function(req, res, next) {
var ImageSearch = require('node-google-image-search');
MongoClient.connect(url, function(err,db){
  db.collection('mycatalog')
    .find({$text: {$search:"FOO" }})
    .toArray(function(err, mdb_results){    
        for (var i=0; i<mdb_results.length; i++){           
            var _search =  mdb_results[i].name ;
            // This search is asynchronous, it won't have returned by the time
            // you return the result below.
            ImageSearch(_search, function(cse){

               // How to add cse.img to mdb_results[i].images ??
               //    mdb_results[i].images = cse;
               // gives undefined

            },0,2);  
        };
        // At this point, ImageSearch has been called, but has not returned results.
        res.send(mdb_results);
        });
    });
});

---

这是有效的，我接受了你的答案-谢谢。你介意详细说明一下cb的情况吗？尽管有效，我还是很难理解到底发生了什么。我更新了这篇文章，试图详细说明。理解回调如何在NodeJS中工作对于理解这里发生的事情至关重要。回调用于指示您已完成工作。感谢您的注释。我仍在努力处理返回回调，这似乎是对自身的调用？我们将回调传递到封闭函数中，然后在没有任何回调函数定义的情况下调用它。如果答案太复杂，无法发表评论，你能推荐一个我可以自学的资源吗？您提供了一个将结果和回调作为参数的函数。回调函数是异步库传入的函数。Async等待您调用该函数以确认您完成了异步工作。在每次迭代中调用回调后，Async就知道您完成了。如果您需要更多信息，请查找更多关于Nodejs回调的文章。这很难理解，但对Nodejs编程至关重要。

[{"name":"FOO", 
  "images":[{"img1":"http://thumbnail1"},{"img2":"http://thumbnail2"}]
},
{"name":"FOOOO", 
  "images":[{"img1":"http://thumbnaila"},{"img2":"http://thumbnailb"}]
}]

router.get('/json', function(req, res, next) {
var ImageSearch = require('node-google-image-search');
MongoClient.connect(url, function(err,db){
  db.collection('mycatalog')
    .find({$text: {$search:"FOO" }})
    .toArray(function(err, mdb_results){    
        for (var i=0; i<mdb_results.length; i++){           
            var _search =  mdb_results[i].name ;
            // This search is asynchronous, it won't have returned by the time
            // you return the result below.
            ImageSearch(_search, function(cse){

               // How to add cse.img to mdb_results[i].images ??
               //    mdb_results[i].images = cse;
               // gives undefined

            },0,2);  
        };
        // At this point, ImageSearch has been called, but has not returned results.
        res.send(mdb_results);
        });
    });
});

router.get('/json', function(req, res, next) {
var ImageSearch = require('node-google-image-search');
MongoClient.connect(url, function(err,db){
  db.collection('mycatalog')
    .find({$text: {$search:"FOO" }})
    .toArray(function(err, mdb_results){
        // async.forEach will iterate through an array and perform an asynchronous action.
        // It waits for you to call callback() to indicate that you are done
        // rather than waiting for it to execute synchronously.
        async.forEach(mdb_results, function (result, callback) {
            ImageSearch(result.name, function(cse){
               // This code doesn't get executed until the network call returns results.
               result.images = cse;
               // This indicate that you are done with this iteration.
               return callback();
            },0,2);  
        },
        // This gets call once callback() is called for each element in the array,
        // so this only gets fired after ImageSearch returns you results.
        function (err) {
            res.send(mdb_results);
        });
    });
});