Underscore js find item by ID

Question

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.

here\'s the data:

{         


        

Answer 1

Update

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.

  // 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

--------------------------------------------
| Chrome | Firefox | Safari |  IE  | Opera |
|--------|---------|--------|------|-------|
|   45   |    25   |  7.1   | Edge |  32   |
--------------------------------------------

More information an polyfill on MDN

---

Update: I found that _.where always returns an array. _.findWhere returns the first object it finds so it will be better to use if you expect a single object in return.

---

You can use _.where It's much easier.

If it's something like this :

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 :

var filteredGoal = _.where(goal, {id: "1"});

Answer 2

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.

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:

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.)

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.

Visit Docs:_.find

Answer 3

Have simplified your data model, but something like this?

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.