javascript - 循环遍历 json 对象时，键没有添加到它

Question

这让我发疯。我有这个 json 对象:

var category_images = {
  "blah": [
    {
      "src": "...",
      "title": "...",
      "alt": "..."
    },
    {
      "src": "...",
      "title": "...",
      "alt": "..."
    }
  ],
  "blah2": [
    {
      "src": "...",
      "title": "...",
      "alt": "..."
    },
    {
      "src": "...",
      "title": "...",
      "alt": "..."
    }
  ]
}

我正在尝试向每个内部 json 对象添加一个新属性，如下所示:

for(var property in category_images){
    for (var i = 0; i < property.length; i++) {
        category_images[property]["new_property"] = "HI";
    }
}

然后像这样保存:

fs.writeFileSync('test.json', JSON.stringify(category_images, null, 4));

但是当我加载文件时没有任何更新...我做错了什么

Answer 1

终于明白了。两个问题:

1. 我的内循环是错误的。条件需要是i < category_images[property].length

2. 我错误地索引了我的子数组。应该这样做category_images[property][i]["src_compressed"] = "HI";

最终结果:

for(var property in category_images){
    console.log(category_images[property].length);
    for (var i = 0; i < category_images[property].length; i++) {
        category_images[property][i]["src_compressed"] = "HI";
    }
}