Question

我试图将新属性附加到某些JSON对象上。我怎么能这样做？

例如，这是我的JSON数组：

var eventsArray;

    eventsArray = [

    {
        "title" : "Marco 1",
        "user": "Marco",
        "start" : "2016-01-12T16:00:00-05:00",
        "end" : "2016-01-12T17:00:00-05:00"
    }, {
        "title" : "Marco 2",
        "user": "Marco",
        "start" : "2016-01-12T10:00:00-05:00",
        "end" : "2016-01-12T12:00:00-05:00"
    }, {
        "title" : "Marta 1",
        "user": "Marta",
        "start" : "2016-01-12T09:00:00-05:00",
        "end" : "2016-01-12T10:00:00-05:00"
    }, {
        "title" : "Marta 2",
        "user": "Marta",
        "start" : "2016-01-13T09:00:00-05:00",
        "end" : "2016-01-13T10:00:00-05:00"
    }, {
        "title" : "Veronica 1",
        "user": "Veronica",
        "start" : "2016-01-12T13:00:00-05:00",
        "end" : "2016-01-12T14:00:00-05:00"
    }, {
        "title" : "Veronica 2",
        "user": "Marco",
        "start" : "2016-01-11T13:00:00-05:00",
        "end" : "2016-01-11T14:00:00-05:00"
    }

    ];

然后我需要添加一个新属性，例如＆＃34; color＆＃34; ：＆＃34;红色＆＃34;用户Veronica，即：

var eventsArray;

eventsArray = [

{
    "title" : "Marco event 1",
    "user": "Marco",
    "start" : "2016-01-12T16:00:00-05:00",
    "end" : "2016-01-12T17:00:00-05:00"
}, {
    "title" : "Marco event 2",
    "user": "Marco",
    "start" : "2016-01-12T10:00:00-05:00",
    "end" : "2016-01-12T12:00:00-05:00"
}, {
    "title" : "Marta event 1",
    "user": "Marta",
    "start" : "2016-01-12T09:00:00-05:00",
    "end" : "2016-01-12T10:00:00-05:00"
}, {
    "title" : "Marta event 2",
    "user": "Marta",
    "start" : "2016-01-13T09:00:00-05:00",
    "end" : "2016-01-13T10:00:00-05:00"
}, {
    "title" : "Veronica event 1",
    "user": "Veronica",
    "start" : "2016-01-12T13:00:00-05:00",
    "end" : "2016-01-12T14:00:00-05:00",
    "color" : "red"
}, {
    "title" : "Veronica event 2",
    "user": "Veronica",
    "start" : "2016-01-11T13:00:00-05:00",
    "end" : "2016-01-11T14:00:00-05:00",
    "color" : "red"
}

];

上面我刚刚添加了（手动）＆＃34;颜色＆＃34; ：＆＃34;红色＆＃34;只对具有＆＃34; user＆＃34;的对象===＆＃34; Veronica＆＃34; （后两者）。我怎么能通过JavaScript做到这一点？

我尝试了一些没有成功的方法，例如：

eventsArray[4].color = "red";
eventsArray[5].color = "red";

或：

eventsArray.user["Veronica"].color = "red";
eventsArray.user["Veronica"].color = "red";

几天后我才开始学习使用JSON。

请注意，在这种特定情况下，具有不同属性的对象不会出现任何问题：我的程序不会爆炸！：P

谢谢。

Answer 1

有很多方法可以做到这一点。

这是一个简单的方法：

eventsArray.forEach( function( event ) {
    if( event.user == 'Veronica' ) event.color = 'red';
});

当然，您可能希望为其他用户和颜色执行此操作。因此，最好将其概括为函数：

function setUserColor( events, user, color ) {
    events.forEach( function( event ) {
        if( event.user == user ) event.color = color;
    });
}

然后你可以这样称呼它：

setUserColor( eventsArray, 'Veronica', 'red' );

现在你也可以为其他用户做同样的事情：

setUserColor( eventsArray, 'Marta', 'green' );

Answer 2

这是一个基本的。

 for(var i = 0; i < eventsArray.length; i++){
   if(eventsArray[i].user === "Veronica" {
      eventsArray[i].color = "red";
   }
 }

如何将新属性添加到JSON数组？

2 个答案: