javascript - 如何在 JavaScript 中使用根节点遍历 json

Question

我有一个带有根节点的 json:

{
"comments":
  [
    {"id":1,"author_name":null,"comment_text":null,"url":"http://localhost:3000/comments/1.json"}
  ]
}

我想遍历每个对象。这是我尝试的:

 var commentNodes = this.props.comments.map(function(comment,index){
            // do something over each object
            );
        });

但它不起作用:

Uncaught TypeError: this.props.comments.map is not a function

Answer 1

你可以像这样用 for 循环遍历它:

data = {
    "comments": [
        {   
            "id": 1,
            "author_name": null,
            "comment_text": null,
            "url": "http://localhost:3000/comments/1.json"
        }, { 
            "id": 2,
            "author_name": null,
            "comment_text": null,
            "url": "http://localhost:3000/comments/2.json"
        }
    ]
}

for (var i = 0; i < data.comments.length; i++) {
    var comment = data.comments[i];

    // do something with the comment
    // console.log(comment.id);
    // console.log(comment.url);
}

或者如果你想获得所有的评论作者，你可以这样做:

var authors = data.comments.map(function(comment) {
    return comment.author_name;
});