Get All Unique Values in a JavaScript Array (Remove Duplicates)

function onlyUnique(value, index, self) {
  return self.indexOf(value) === index;
}

// usage example:
var a = ['a', 1, 'a', 2, '1'];
var unique = a.filter(onlyUnique);

console.log(unique); // ['a', 1, 2, '1']

Remove duplicate values from JS array

Quick and dirty using jQuery:

var names = ["Mike","Matt","Nancy","Adam","Jenny","Nancy","Carl"];
var uniqueNames = [];
$.each(names, function(i, el){
    if($.inArray(el, uniqueNames) === -1) uniqueNames.push(el);
});

Filter array to have unique values

You can use Array.filter function to filter out elements of an array based on the return value of a callback function. The callback function runs for every element of the original array.

The logic for the callback function here is that if the indexOf value for current item is same as the index, it means the element has been encountered first time, so it can be considered unique. If not, it means the element has been encountered already, so should be discarded now.

var arr = ["X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11", "X_row7", "X_row4", "X_row6", "X_row10", "X_row8", "X_row9", "X_row11"];
var filteredArray = arr.filter(function(item, pos){  return arr.indexOf(item)== pos; });
console.log( filteredArray );

Array.prototype.contains = function(v) {  for (var i = 0; i < this.length; i++) {    if (this[i] === v) return true;  }  return false;};
Array.prototype.unique = function() {  var arr = [];  for (var i = 0; i < this.length; i++) {    if (!arr.contains(this[i])) {      arr.push(this[i]);    }  }  return arr;}
var duplicates = [1, 3, 4, 2, 1, 2, 3, 8];var uniques = duplicates.unique(); // result = [1,3,4,2,8]
console.log(uniques);

const findDuplicates = (arr) => {  let sorted_arr = arr.slice().sort(); // You can define the comparing function here.   // JS by default uses a crappy string compare.  // (we use slice to clone the array so the  // original array won't be modified)  let results = [];  for (let i = 0; i < sorted_arr.length - 1; i++) {    if (sorted_arr[i + 1] == sorted_arr[i]) {      results.push(sorted_arr[i]);    }  }  return results;}
let duplicatedArray = [9, 9, 111, 2, 3, 4, 4, 5, 7];console.log(`The duplicates in ${duplicatedArray} are ${findDuplicates(duplicatedArray)}`);

let arr =   [  [    "s1@example.com",    "s2@example.com"  ],  [    "s1@example.com",    "s3@example.com"  ]]
let arr2 = [...new Set(arr.flat(1))];console.log(arr2)

const coords = [{x: 260, y: 60}, {x: 180, y: 0}, {x: 180, y: 240}, {x: 360, y: 120}, {x: 180, y: 60}, {x: 180, y: 60}, {x: 180, y: 60}];

const dedup = [...coords.reduce((map, { x, y }) => {
   return (map.set(`${x}-${y}`, { x, y }));
}, new Map()).values()];

console.log('De-duplicated:', dedup)
     

.as-console-wrapper { max-height: 100% !important; top: 0; }

function onlyUnique(value, index, self) {
  return self.indexOf(value) === index;
}

// usage example:
var a = ['a', 1, 'a', 2, '1'];
var unique = a.filter(onlyUnique);

console.log(unique); // ['a', 1, 2, '1']

const obj = {};

for (let i = 0, len = things.thing.length; i < len; i++) {
  obj[things.thing[i]['place']] = things.thing[i];
}

things.thing = new Array();

 for (const key in obj) { 
   things.thing.push(obj[key]);
}