41

我是 Underscore js 的新手，对如何使用它有点困惑。我有一组“目标”，我想通过 ID 找到其中一个。

这是数据：

{"goal":[
    {
        "category" : "education",
        "title" : "Charlie University",
        "description" : "Lorem ipsum dolor sit amet",
        "date" : "01/03/2020",
        "value" : 50000,
        "achievability" : 3,
        "experimental_achievability": 3,
        "suggested": false,
        "accounts": [
            {
                ...
            },
            {
                ...
            }
        ],
        "articles": [
            {
                ...
            },
            {
                ...
            },
            {
                ...
            }
        ],
        "related_goals": [
            {
                ...
            }
        ],
        "id":"1"
    },
    {
        "category" : "family",
        "title" : "Getting married",
        "description" : "Lorem ipsum dolor sit amet",
        "date" : "01/03/2022",
        "value" : 10000,
        "achievability" : 3,
        "experimental_achievability": 2,
        "suggested": true,
        "accounts": [
            {
                ...
            }
        ],
        "articles": [
            {
                ...
            },
            {
                ...
            },
            {
                ...
            }
        ],
        "related_goals": [
            {
                ...
            }
        ],
        "id":"2"
    }
    ...
]}

这就是我正在尝试的，我想获取整个数组/对象，以便我可以获取它的每个字段：

var goalId = 1;
_.each(result.goal, function(item){
    _.find(result.goal, function(i){
         return i = goalId;
    });
});

知道怎么做吗？

4

3 回答 3

99

更新

现在是 2016 年，我们可能不需要下划线来实现这一目标。使用Array.prototype.find(). 如果数组中的元素满足提供的测试功能，则返回数组中的值。否则返回未定义。

  // Underscore
  var users = [
    { 'user': 'barney',  'age': 36, 'active': true },
    { 'user': 'fred',    'age': 40, 'active': false },
    { 'user': 'pebbles', 'age': 1,  'active': true }
  ]

  _.find(users, function (o) { return o.age < 40; })
  // output: object for 'barney'

  // Native
  var users = [
    { 'user': 'barney',  'age': 36, 'active': true },
    { 'user': 'fred',    'age': 40, 'active': false },
    { 'user': 'pebbles', 'age': 1,  'active': true }
  ]

  users.find(function (o) { return o.age < 40; })
  // output: object for 'barney'

浏览器支持

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|   45   |    25   |  7.1   | Edge |  32   |
--------------------------------------------

更多信息MDN上的 polyfill

更新：我发现_.where总是返回一个数组。_.findWhere返回它找到的第一个对象，因此如果您期望返回单个对象，则使用它会更好。

你可以使用_.where它更容易。

如果是这样的：

var goal  = [

    {
        "category" : "education",
        "title" : "Charlie University",
        "description" : "Lorem ipsum dolor sit amet",
        "date" : "01/03/2020",
        "value" : 50000,
        "achievability" : 3,
        "experimental_achievability": 3,
        "suggested": false,
        "accounts": [],
        "articles": [],
        "related_goals": [],
        "id":"1"
    },
    {
        "category" : "education",
        "title" : "Charlie University",
        "description" : "Lorem ipsum dolor sit amet",
        "date" : "01/03/2020",
        "value" : 50000,
        "achievability" : 3,
        "experimental_achievability": 3,
        "suggested": false,
        "accounts": [],
        "articles": [],
        "related_goals": [],
        "id":"2"
    },
    {
        "category" : "education",
        "title" : "Charlie University",
        "description" : "Lorem ipsum dolor sit amet",
        "date" : "01/03/2020",
        "value" : 50000,
        "achievability" : 3,
        "experimental_achievability": 3,
        "suggested": false,
        "accounts": [],
        "articles": [],
        "related_goals": [],
        "id":"3"
    },
    {
        "category" : "education",
        "title" : "Charlie University",
        "description" : "Lorem ipsum dolor sit amet",
        "date" : "01/03/2020",
        "value" : 50000,
        "achievability" : 3,
        "experimental_achievability": 3,
        "suggested": false,
        "accounts": [],
        "articles": [],
        "related_goals": [],
        "id":"4"
    }
]

你可以使用类似的东西：

var filteredGoal = _.where(goal, {id: "1"});
于 2012-10-05T10:49:28.350 回答
21

您正在使用对象数组。所以，你可以使用：_。findWhere（查看列表并返回匹配所有键值对的第一个值）以获取基于 id 或其他键属性的所有属性。

var some= [
             {Employee:'ved',id:20}, 
             {Employee:"ved",age:25},
             {Employee:"p",age:2}
          ];

var a = _.findWhere(some,{id:20});
console.log('searchResult',a);

要获取索引，您可以使用以下内容：

var b = _.indexOf(some,a);
console.log('index',b);

如果您需要所有使用列表，
请尝试： _. where（它查看数组中的每个匹配项，返回包含属性中列出的键值对的所有值的数组。）

var some= [ 
            {Employee:"ved",id:20}, 
            {Employee:"ved prakash",id:20},
            {Employee:"anyone",id:2}
          ];
var a = _.where(some,{id:25});
    console.log('searchResult',a);

_.find：它只用于检查值，而不是同时检查键值。


访问文档： _. find

于 2014-08-21T07:18:07.613 回答
15

已经简化了您的数据模型，但是像这样？

var goals = [{id:1, name:'Goal1'},
             {id:2, name:'Goal2'},
             {id:3, name:'Goal3'}];

function getGoal(id) {
    return _.find(goals, function(goal) {
        return goal.id === id;
    });
}

alert(getGoal(2).name);

您可以在这个jsFiddle中看到这一点。

于 2012-10-05T10:47:46.220 回答