如何使用 jquery 从外部 json 文件加载数据？

Question

这是我的 app.js 文件

$(document).ready(function () {
        $.getJSON("http://localhost:3000/db.json", function (data) {

        $(data.as).each(function (index, value) {

            console.log(value);
        });
    });
});

这是 db.json 文件

{
  "as": [
    {
      "imageID": "1",
      "imageSource": "Popular Science 1",
      "alt": "Science 1"
    },
    {
      "imageID": "2",
      "imageSource": "Popular Science 2",
      "alt": "Science 2"
    }
  ]
}

如何只获取例如Popular Science 2？ 如果我写console.log(value[1]);，则会显示错误。如何索引一个数组？

Answer 1

你可以简单地使用：

value.imageSource

因为value是这里的对象。

const data = {as:[{imageID:"1",imageSource:"Popular Science 1",alt:"Science 1"},{imageID:"2",imageSource:"Popular Science 2",alt:"Science 2"}]};

$(data.as).each(function(index, value) {
  console.log(value.imageSource);
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>

---

如果你只想要Popular Science 2，那么就不需要循环了。你可以这样做：

const data = {as:[{imageID:"1",imageSource:"Popular Science 1",alt:"Science 1"},{imageID:"2",imageSource:"Popular Science 2",alt:"Science 2"}]};

console.log( data.as[1].imageSource );

或者，通过一些验证，例如：

const data = {as:[{imageID:"1",imageSource:"Popular Science 1",alt:"Science 1"},{imageID:"2",imageSource:"Popular Science 2",alt:"Science 2"}]};

// Vlidating that we actually have an array and data as index 1
if( data && data.as && data.as.length > 1){ 
  console.log( data.as[1].imageSource );
}