javascript - 为什么对象值被插入数组 3 次？

Question

我有一个简单的对象数组，我将一个包含 2 个字段的对象插入其中:bucketName 和 Date。问题在于这些值被三次插入数组中。请帮我。

JS:

sortBucket: function(bucketList) {
    var counter, j = 0;
    var str = "aws-billing-csv";
    console.log("Bucket List :: ", bucketList);

    bucketList.forEach(function(bucket, index) {
        (function(bucketId) {
            var bucketObj = {};
            // console.log("Bucket Id :: ",bucketId);
            s3Client.listObjects(params = {Bucket: bucketId }, function(err, data) {
                var csvBucketArr = [];
                if (err) {
                    document.getElementById('status').innerHTML = 'Could not load objects from ' + bucketID;
                }
                else{        
                    //console.log("Bucket Data "+index+" :: ",data);
                    data.Contents.forEach(function(content,contentIndex){
                        var fileKey = content.Key;
                        if(fileKey.search(str) != -1) {
                            // console.log("fileKey["+bucketId+"] "+contentIndex+" :: ",fileKey + "  Date :: " ,content.LastModified);
                            bucketObj[fileKey] = {
                                lastModified    : content.LastModified,
                                bucketName      : bucketId
                            }
                            if(!jQuery.isEmptyObject(bucketObj)){
                                csvBucketArr.push(bucketObj);
                            }
                        }
                    });
                    csv = csvBucketArr;
                  }
                  if(csvBucketArr.length!==0)
                      console.log("csvBucketArr :: ",csvBucketArr));
                  });
             }(bucket.bucketName));
            // console.log("Bucket " + index + " :: ", bucket);
          });
       },

Answer 1

您在每次迭代中将相同的对象插入数组:

data.Contents.forEach(function(content,contentIndex){...});

因此，.forEach() 循环迭代多少次，最终都会将完全相同的 bucketObj 对象插入 csvBucketArr数组。

如果您希望 .forEach() 的每次迭代都将一个新的不同的 bucketObj 对象放入数组中，那么您每次都需要创建一个新对象在这个循环中，如下所示:

sortBucket: function(bucketList) {
    var counter, j = 0;
    var str = "aws-billing-csv";
    console.log("Bucket List :: ", bucketList);

    bucketList.forEach(function(bucket, index) {
        (function(bucketId) {
            // console.log("Bucket Id :: ",bucketId);
            s3Client.listObjects(params = {Bucket: bucketId }, function(err, data) {
                var csvBucketArr = [];
                if (err) {
                    document.getElementById('status').innerHTML = 'Could not load objects from ' + bucketID;
                }
                else{        
                    //console.log("Bucket Data "+index+" :: ",data);
                    data.Contents.forEach(function(content,contentIndex){
                        // ===> create new bucketObj object
                        var bucketObj = {};
                        var fileKey = content.Key;
                        if(fileKey.search(str) != -1) {
                            // console.log("fileKey["+bucketId+"] "+contentIndex+" :: ",fileKey + "  Date :: " ,content.LastModified);
                            bucketObj[fileKey] = {
                                lastModified    : content.LastModified,
                                bucketName      : bucketId
                            }
                            if(!jQuery.isEmptyObject(bucketObj)){
                                csvBucketArr.push(bucketObj);
                            }
                        }
                    });
                    csv = csvBucketArr;
                  }
                  if(csvBucketArr.length!==0)
                      console.log("csvBucketArr :: ",csvBucketArr));
                  });
             }(bucket.bucketName));
            // console.log("Bucket " + index + " :: ", bucket);
          });
       },