constfindDuplicates=(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 =[9,4,111,2,3,4,9,5,7];console.log(`The duplicates in ${duplicatedArray} are ${findDuplicates(duplicatedArray)}`);
how to get duplicate values from array in javascript
const arr =["q","w","w","e","i","u","r"]
arr.reduce((acc, cur)=>{if(acc[cur]){
acc.duplicates.push(cur)}else{
acc[cur]=true//anything could go here}},{duplicates:[]})
constfindDuplicates=(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 =[9,4,111,2,3,9,4,5,7];console.log(`The duplicates in ${duplicatedArray} are ${findDuplicates(duplicatedArray)}`);
javascript how find the index of duplicate elements in array
// A method to find a duplicate value in an array and the index of the duplicates// array can be any data typeconst arry =["1","2","3","1"];let set =newSet();for(let i =0; i < arry.length; i++){let pastSize = set.size;
set.add(arry[i]);let newSize = set.size;if(pastSize == newSize){console.log("The array has duplicates at index: ", i);}}