Javascript 下划线js通过ID查找项目
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Underscore js find item by ID
提问by Mauro74
I'm new to Underscore js and bit confused on how to use it. I have a collection of 'goals' and I want to find one of it by ID.
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。
here's the data:
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"
}
...
]}
That's what I'm trying, I want to get the entire array/object so I can get each field of it:
这就是我正在尝试的，我想获取整个数组/对象，以便获取它的每个字段：
var goalId = 1;
_.each(result.goal, function(item){
_.find(result.goal, function(i){
return i = goalId;
});
});
Any idea how to do it?
知道怎么做吗？
回答by Ahmad Alfy
Update
更新
It's 2016 and we might not acutally need underscore to achieve that. Using Array.prototype.find(). It returns a value in the array, if an element in the array satisfies the provided testing function. Otherwise undefined is returned.
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函数，则返回数组中的值。否则返回 undefined。
// 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'
Browser support
浏览器支持
--------------------------------------------
| Chrome | Firefox | Safari | IE | Opera |
|--------|---------|--------|------|-------|
| 45 | 25 | 7.1 | Edge | 32 |
--------------------------------------------
More information an polyfill on MDN
更多关于MDN的 polyfill 信息
Update: I found that _.wherealways returns an array. _.findWherereturns the first object it finds so it will be better to use if you expect a single object in return.
更新：我发现它_.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，最好使用它。
You can use _.whereIt's much easier.
你可以使用_.where它更容易。
If it's something like this :
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"
}
]
You can use something like :
你可以使用类似的东西：
var filteredGoal = _.where(goal, {id: "1"});
回答by Ved
You are using Array of objects. So,you can use: _.findWhere(Looks through the list and returns the first value that matches all of the key-value pairs ) to get the all the properties based on id or other key attribute.
您正在使用对象数组。所以，你可以使用：_。findWhere（查看列表并返回与所有键值对匹配的第一个值）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);
To get the index, you can use something like this:
要获取索引，您可以使用以下内容：
var b = _.indexOf(some,a);
console.log('index',b);
If you need all list of uses,
TRY: _.where(It looks through each occurrence in the array, returning an array of all the values that contain the key-value pairs listed in properties.)
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: It is used to check the value only, not Key-value both.
_.find：仅用于检查值，不用于检查Key-value。
Visit Docs:_.find
访问文档：_.find
回答by Gwyn Howell
Have simplified your data model, but something like this?
简化了你的数据模型，但像这样吗？
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);
You can see this in action in this jsFiddle.
你可以在这个jsFiddle 中看到这一点。
