Removing Duplicate Objects with Underscore for JavaScript

Underscore.js, remove duplicates in array of objects based on key value

With Underscore, use _.uniq with a custom transformation, a function like _.property('name') would do nicely or just 'name', as @Gruff Bunny noted in the comments :

var mySubArray = _.uniq(myArray, 'name');

And a demo http://jsfiddle.net/nikoshr/02ugrbzr/

If you use Lodash and not Underscore, go with the example given by @Jacob van Lingen in the comments and use _.uniqBy:

var mySubArray = _.uniqBy(myArray, 'name')

Remove duplicates from object array - Underscore

Because two objects are not == or ===, just because they have the same keys, you will need to use the [iterator] argument of the uniq() function;

_.uniq(myArray, function (item) {
    return item.x + item.y;
});

Note you'll need to return a unique string combination; consider the case of { x: 11, y: 1 } and { x: 1, y: 11 }; my code will resolve both to 111, and treat them as the same.

Something like:

_.uniq(myArray, function (item) {
    return 'x:' + item.x + 'y:' + item.y;
});

... would be more resilient, but it depends on the values of your data, of course.

How to remove duplicate item form array of string objects with _underscoreJS

You can use Array.map to groups arrays, Array.flat to marge arrays and Set to remove duplicate.

let input1 = ["PC", "PS3,Xbox 360,PC,PS4,Xbox One,Nintendo Switch", "PC,PS4,Xbox One,Nintendo Switch", "PS4,PC", "PS4,PS5,Xbox One,Nintendo Switch,PC", "PC,PS4,Xbox One", "PC,Android"];
let input2 = { "data": [{ "userId": 8, "game": "League of legends", "playTime": 500, "genre": "MOBA", "platforms": ["PC"] }, { "userId": 7, "game": "World of warcraft", "playTime": 1500, "genre": "MMORPG", "platforms": ["PC"] }, { "userId": 88, "game": "Dark Souls", "playTime": 109, "genre": "Action RPG", "platforms": ["PS3", "Xbox 360", "PC", "PS4", "Xbox One", "Nintendo Switch"] }, { "userId": 88, "game": "The Witcher 3: Wild Hunt", "playTime": 9, "genre": "RPG", "platforms": ["PC", "PS4", "Xbox One", "Nintendo Switch"] }, { "userId": 1, "game": "The last of us 2", "playTime": 100, "genre": "FPS", "platforms": ["PS4", "PC"] }, { "userId": 7, "game": "Hitman 3", "playTime": 60, "genre": "Stealth", "platforms": ["PS4", "PS5", "Xbox One", "Nintendo Switch", "PC"] }, { "userId": 99, "game": "Minecraft", "playTime": 1002, "genre": "Sandbox", "platforms": ["PC"] }, { "userId": 7, "game": "Hearthstone", "playTime": 1000, "genre": "Card Game", "platforms": ["PC"] }, { "userId": 7, "game": "FIFA", "playTime": 2000, "genre": "Sport", "platforms": ["PC", "PS4", "Xbox One"] }, { "userId": 2, "game": "The Witcher 3: Wild Hunt", "playTime": 78, "genre": "RPG", "platforms": ["PC", "PS4", "Xbox One", "Nintendo Switch"] }, { "userId": 47, "game": "League of legends", "playTime": 850, "genre": "MOBA", "platforms": ["PC"] }, { "userId": 2, "game": "Among Us", "playTime": 5000, "genre": "Multiplayer", "platforms": ["PC", "Android"] }, { "userId": 2, "game": "Valorant", "playTime": 2000, "genre": "FPS", "platforms": ["PC"] }, { "userId": 9, "game": "Valorant", "playTime": 80, "genre": "FPS", "platforms": ["PC"] }, { "userId": 9, "game": "Dark Souls", "playTime": 109, "genre": "RPG", "platforms": ["PS3", "Xbox 360", "PC", "PS4", "Xbox One", "Nintendo Switch"] }, { "userId": 9, "game": "The Witcher 3: Wild Hunt", "playTime": 900, "genre": "RPG", "platforms": ["PC", "PS4", "Xbox One", "Nintendo Switch"] }, { "userId": 24, "game": "League of legends", "playTime": 300, "genre": "MOBA", "platforms": ["PC"] }, { "userId": 24, "game": "World of warcraft", "playTime": 800, "genre": "MMORPG", "platforms": ["PC"] }, { "userId": 54, "game": "Minecraft", "playTime": 231, "genre": "Sandbox", "platforms": ["PC"] }, { "userId": 7, "game": "Minecraft", "playTime": 777, "genre": "Sandbox", "platforms": ["PC"] }, { "userId": 7, "game": "Hitman 3", "playTime": 90, "genre": "Stealth", "platforms": ["PS4", "PS5", "Xbox One", "Nintendo Switch", "PC"] }] }

let removeDuplicate = (array, procedure) => [...new Set(array.map(procedure).flat())];

let result1 = removeDuplicate(input1, item => item.split(","));
let result2 = removeDuplicate(input2.data, ({ platforms }) => platforms);

console.log({ result1, result2 });

Underscore: Remove object having some duplicate properties

For example:

_.uniq(data, function(x) { return x.LATITUDE + "/" + x.LONGITUDE })

Basically, you provide a function that is supposed to return a hash value based on selected properties.

Filter unique & duplicate objects in array using underscore

It might be easier to introduce a temporary variable to hold the groups:

var data = [{"origin":"SJU","dest":"JFK","rank":48},{"origin":"JFK","dest":"SJU","rank":21},{"origin":"IAD","dest":"LAX","rank":31},{"origin":"LAS","dest":"SJU","rank":21}]

var groups = _.groupBy(data, function(item) {
  return [item.origin, item.dest].sort();
});

Then:

var duplicates = [],
singles = [];

_.each(groups, function(group) {
  if (group.length > 1) {
    duplicates.push.apply(duplicates, group);
  } else {
    singles.push(group[0]);
  }
});

Demo

Remove duplicates from JavaScript Array of Objects based on Key

From the little that i understand.
you can use reduce for this

check the code snippet

var fileList = [{    identifier: "auto-1",    file: "mp.mp3"  },  {    identifier: "auto-2",    file: "ss.mp3"  },  {    identifier: "auto-3",    file: "mj.mp3"  },  {    identifier: "type1",    file: "ss.mp3"  },  {    identifier: "type2",    file: "squirrel-chatter.mp3"  },  {    identifier: "type3",    file: "mj.mp3"  }]var fileList2 = [{  identifier: "auto-1",  file: "mp.mp3"}, {  identifier: "type1",  file: "mp.mp3"}]
var result;
result = fileList2.reduce(function callback(result, key, index, keysArray) {  debugger;  let indx = result.findIndex((item) => item.file === key.file)  if (indx > -1) {    result[indx].identifier = (key.identifier.includes("type")) ? key.identifier : result[indx].identifier  } else {    result.push(key)  }  return result}, [])
console.log(result)

Remove duplicates in an object array Javascript

Vanilla JS version:

const list = [{x:1,y:2}, {x:3,y:4}, {x:5,y:6}, {x:1,y:2}];
function dedupe(arr) {  return arr.reduce(function(p, c) {
    // create an identifying id from the object values    var id = [c.x, c.y].join('|');
    // if the id is not found in the temp array    // add the object to the output array    // and add the key to the temp array    if (p.temp.indexOf(id) === -1) {      p.out.push(c);      p.temp.push(id);    }    return p;
    // return the deduped array  }, {    temp: [],    out: []  }).out;}
console.log(dedupe(list));