const names = ['John', 'Paul', 'George', 'Ringo', 'John'];
let unique = [...new Set(names)];
console.log(unique); // 'John', 'Paul', 'George', 'Ringo'const names = ['John', 'Paul', 'George', 'Ringo', 'John'];
function removeDups(names) {
let unique = {};
names.forEach(function(i) {
if(!unique[i]) {
unique[i] = true;
}
});
return Object.keys(unique);
}
removeDups(names); // // 'John', 'Paul', 'George', 'Ringo'let a = [10,20,30,10,30];
let b = [... new Set(a)];
console.log(b);function getNotUnique(array) {
var map = new Map();
array.forEach(a => map.set(a, (map.get(a) || 0) + 1));
return array.filter(a => map.get(a) > 1);
}
console.log(getNotUnique([1, 2, 2, 4, 4])); //[2, 2, 4, 4]
console.log(getNotUnique([1, 2, 3] )); //[]let a = [10,20,30,10,30];
let b = a.filter((item,index) => a.indexOf(item) === index);
console.log(b); let a = [10,20,30,50,30];
let b = a.reduce((unique,item) => unique.includes(item) ? unique: [... unique, item] ,[]);
console.log(b);