在D3循环中加载多个JSON文件:索引总是最后一个

I'm trying to create many charts each with different JSON data. I have a loop which tries to load the data for each chart, but although the calls are asynchronous, the loop index is always the last one. Instead of doing 0,1,2,3,4,5 it does 5,5,5,5,5,5. Here's an example with 2 items to loop over:I'm trying to create many charts each with diff