Lodash remove duplicates from array

问题

This is my data:

[
    {
        url: 'www.example.com/hello',
        id: "22"    
    },
    {
        url: 'www.example.com/hello',
        id: "22"    
    },
    {
        url: 'www.example.com/hello-how-are-you',
        id: "23"    
    },
    {
        url: 'www.example.com/i-like-cats',
        id: "24"    
    },
    {
        url: 'www.example.com/i-like-pie',
        id: "25"    
    }
]

With Lodash, how could I remove objects with duplicate id keys? Something with filter, map and unique, but not quite sure.

My real data set is much larger and has more keys, but the concept should be the same.

回答1:

_.unique no longer work for the current version as lodash 4.0.0 has this breaking change. The functionally was splitted into _.uniq, _.sortedUniq, _.sortedUniqBy, & _.uniqBy

You could use _.uniqBy either by

_.uniqBy(data, function (e) {
  return e.id;
});

_.uniqBy(data, 'id');

Documentation: https://lodash.com/docs#uniqBy

For older versions of lodash( < 4.0.0 )

Assuming that the data should be unique by id and your data is stored in data variable, you can use unique() function like this:

_.unique(data, function (e) {
  return e.id;
});

Or simply

_.uniq(data, 'id');

回答2:

You could use lodash method _.uniqWith, it is available in the current version of lodash 4.17.2.

Example:

var objects = [{ 'x': 1, 'y': 2 }, { 'x': 2, 'y': 1 }, { 'x': 1, 'y': 2 }];

_.uniqWith(objects, _.isEqual);
// => [{ 'x': 1, 'y': 2 }, { 'x': 2, 'y': 1 }]

More info: https://lodash.com/docs/#uniqWith

回答3:

Or simply Use union, for simple array.

回答4:

Simply use _.uniqBy(). It creates duplicate-free version of an array.

This is a new way and available from 4.0.0 version.

_.uniqBy(data, 'id');

_.uniqBy(data, obj => obj.id);

回答5:

You can also use unionBy for 4.0.0 and later, as follows: let uniques = _.unionBy(data, 'id')

回答6:

With lodash version 4+, you would remove duplicate objects either by specific property or by the entire object like so:

var users = [
  {id:1,name:'ted'},
  {id:1,name:'ted'},
  {id:1,name:'bob'},
  {id:3,name:'sara'}
];
var uniqueUsersByID = _.uniqBy(users,'id'); //removed if had duplicate id
var uniqueUsers = _.uniqWith(users, _.isEqual);//removed complete duplicates

Source:https://www.codegrepper.com/?search_term=Lodash+remove+duplicates+from+array

来源：https://stackoverflow.com/questions/31740155/lodash-remove-duplicates-from-array

标签

javascript

lodash