[javascript] Remove an item from array using UnderscoreJS

Say I have this code

var arr = [{id:1,name:'a'},{id:2,name:'b'},{id:3,name:'c'}];

and I want to remove the item with id = 3 from the array. Is there a way of doing this without splicing? Maye something using underscore or something like that?

Thanks!

You can use reject method of Underscore, below will return a new array which won't have array with particular match

arr = _.reject(arr, function(objArr){ return objArr.id == 3; });

Use can use plain JavaScript's Array#filter method like this:

var arr = [{id:1,name:'a'},{id:2,name:'b'},{id:3,name:'c'}];_x000D_
_x000D_
var filteredArr = arr.filter(obj => obj.id != 3);_x000D_
_x000D_
console.log(filteredArr);

Or, use Array#reduce and Array#concat methods like this:

var arr = [{id:1,name:'a'},{id:2,name:'b'},{id:3,name:'c'}];_x000D_
_x000D_
var reducedArr = arr.reduce((accumulator, currObj) => {_x000D_
  return (currObj.id != 3) ? accumulator.concat(currObj) : accumulator;_x000D_
}, []);_x000D_
_x000D_
console.log(reducedArr);

NOTE:

• Both of these are pure functional approach (i.e. they don't modify the existing array).
• No, external library is required in these approach (Vanilla JavaScript is enough).

Other answers create a new copy of the array, if you want to modify the array in place you can use:

arr.splice(_.findIndex(arr, { id: 3 }), 1);

But that assumes that the element will always be found inside the array (because if is not found it will still remove the last element). To be safe you can use:

var index = _.findIndex(arr, { id: 3 });
if (index > -1) {
    arr.splice(index, 1);
}

or another handy way:

_.omit(arr, _.findWhere(arr, {id: 3}));

my 2 cents

You can use Underscore .filter

    var arr = [{
      id: 1,
      name: 'a'
    }, {
      id: 2,
      name: 'b'
    }, {
      id: 3,
      name: 'c'
    }];

    var filtered = _(arr).filter(function(item) {
         return item.id !== 3
    });

Can also be written as:

var filtered = arr.filter(function(item) {
    return item.id !== 3
});

var filtered = _.filter(arr, function(item) {
    return item.id !== 3
});

Check Fiddle

You can also use .reject

Use Underscore _.reject():

arr = _.reject(arr, function(d){ return d.id === 3; });

I used to try this method

_.filter(data, function(d) { return d.name != 'a' });

There might be better methods too like the above solutions provided by users

By Using underscore.js

var arr = [{id:1,name:'a'},{id:2,name:'b'},{id:3,name:'c'}];

var resultArr = _.reject(arr,{id:3});

console.log(resultArr);

The result will be :: [{id:1name:'a'},{id:2,name:'c'}]

Please exercise care if you are filtering strings and looking for case insensitive filters. _.without() is case sensitive. You can also use _.reject() as shown below.

var arr = ["test","test1","test2"];

var filtered = _.filter(arr, function(arrItem) {
    return arrItem.toLowerCase() !== "TEST".toLowerCase();
});
console.log(filtered);
// ["test1", "test2"]

var filtered1 = _.without(arr,"TEST");
console.log(filtered1);
// ["test", "test1", "test2"]

var filtered2 = _.reject(arr, function(arrItem){ 
    return arrItem.toLowerCase() === "TEST".toLowerCase();
});
console.log(filtered2);
// ["test1", "test2"]

Underscore has a _without() method perfect for removing an item from an array, especially if you have the object to remove.

Returns a copy of the array with all instances of the values removed.

_.without(["bob", "sam", "fred"], "sam");

=> ["bob", "fred"]

Works with more complex objects too.

var bob = { Name: "Bob", Age: 35 };
var sam = { Name: "Sam", Age: 19 };
var fred = { Name: "Fred", Age: 50 };

var people = [bob, sam, fred]

_.without(people, sam);

=> [{ Name: "Bob", Age: 35 }, { Name: "Fred", Age: 50 }];

If you don't have the item to remove, just a property of it, you can use _.findWhere and then _.without.