Remove duplicate values from an array of objects in javascript [duplicate]

Answer 1

const things = {
  thing: [
    { id: '12345', name: 'First name' },
    { id: '12345', name: 'Second name' },
    { id: '34536', name: 'Third name' }, 
  ],
};

const RemoveDuplicates = (array, key) => {
  return array.reduce((arr, item) => {
    const removed = arr.filter(i => i[key] !== item[key]);
    return [...removed, item];
  }, []);
};

console.log(RemoveDuplicates(things.thing, 'id'));

Answer 2

You can use array#reduce and array#some.

const arr = [
    {label: 'All', value: 'All'},
    {label: 'All', value: 'All'},
    {label: 'Alex', value: 'Ninja'},
    {label: 'Bill', value: 'Op'},
    {label: 'Cill', value: 'iopop'}
]

var result = arr.reduce((unique, o) => {
    if(!unique.some(obj => obj.label === o.label && obj.value === o.value)) {
      unique.push(o);
    }
    return unique;
},[]);
console.log(result);

Answer 3

One liner solutions for ES6+

Unique by label and value

arr.filter((v,i,a)=>a.findIndex(t=>(t.label === v.label && t.value===v.value))===i)

Unique by all properties of the object:

arr.filter((v,i,a)=>a.findIndex(t=>(JSON.stringify(t) === JSON.stringify(v)))===i)

Answer 4

ES1 compatible :

const a = [
    {label: 'All', value: 'All'},
    {label: 'All', value: 'All'},
    {label: 'Alex', value: 'Ninja'},
    {label: 'Alex', value: 'Ninja'},
    {label: 'Alex', value: 'Ninja'}
]

for (let i = 0; i < a.length; ++i)
    for (let j = 0; j < a.length; ++j)
        if (i !== j && a[i].label === a[j].label && a[i].value === a[j].value)
            a.splice(j, 1);            
console.log(a);

Answer 5

This code worked for me,

const addresses = [...]; // Some array I got from async call

const uniqueAddresses = Array.from(new Set(addresses.map(a => a.id)))
 .map(id => {
   return addresses.find(a => a.id === id)
 })

Answer 6

function removeDuplicates(array, key) {
   let lookup = {};
   array.forEach(element => {
     lookup[element[key]] = element
   });
   return Object.keys(lookup).map(key => lookup[key]);
};

removeDuplicates(array,'objectKey');